A Phase 1/2, Randomized, Observer-blind, Active-Control Study to Evaluate the Safety, Reactogenicity, and Immunogenicity of mRNA-based Influenza and SARS-CoV-2 Multi-component Vaccines in Healthy Adults
Phase: PHASE1
Conditions: SARS-CoV-2, Influenza
Sponsor: ModernaTX, Inc.

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mRNA-1083-P101 Protocol Amendment 2 
mRNA-1083 
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Page 1 
CLINICAL STUDY PROTOCOL 
Protocol Title: 
A Phase 1/2, Randomized, Observer-blind, Active-Control 
Study to Evaluate the Safety, Reactogenicity, and 
Immunogenicity of mRNA-based Influenza and SARS-
CoV-2 Multi-component Vaccines in Healthy Adults 
Protocol Number: 
mRNA-1083-P101 
Compound: 
mRNA-1083 
Brief Title: 
A clinical trial to investigate how safe a new SARS-CoV-
2 and influenza vaccine (mRNA-1083) is and whether it 
helps the immune system fight viruses in healthy adult 
participants 
Study Phase: 
Phase 1/2 
Sponsor Name: 
ModernaTX, Inc. 
Legal Registered 
Address: 
200 Technology Square 
Cambridge, MA 02139 
Regulatory Agency 
Identifier Number: 
IND: 29324 
Date: 
14 Mar 2024 
Sponsor Signatory: 
See e-Signature and date signed on last page the document. 
Sponsor Signatory and Contact Information will be provided separately. 
CONFIDENTIAL 
This document contains confidential information, which should not be copied, referred to, 
released to, or published by anyone without written approval from ModernaTX, Inc. 
NCT05827926

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DECLARATION OF INVESTIGATOR  
I have read and understood all sections of the protocol entitled A Phase 1/2, Randomized, 
Observer-blind, Active-Control Study to Evaluate the Safety, Reactogenicity, and 
Immunogenicity of mRNA-based Influenza and SARS-CoV-2 Multi-component Vaccines in 
Healthy Adults” dated 14 Mar 2024 and the most recent version of the mRNA-1083 
Investigator’s Brochure. 
I agree to supervise all aspects of the protocol and to conduct the clinical investigation in 
accordance with the current protocol, the International Council for Harmonisation (ICH) of 
Technical Requirements for Registration of Pharmaceuticals for Human Use, E6(R2) Good 
Clinical Practice (GCP) Guidance, and all applicable local and country regulations. I will not 
make changes to the protocol before consulting with ModernaTX, Inc. or implement protocol 
changes without institutional review board (IRB) or independent ethics committee (IEC) 
approval except to eliminate an immediate risk to participants. I agree to administer study 
treatment only to participants under my personal supervision or the supervision of a 
subinvestigator. I will not supply study treatment to any person not authorized to receive it. I also 
agree that persons debarred from conducting or working on clinical studies by any court or 
regulatory agency will not be allowed to conduct or work on studies for the Sponsor or a 
partnership in which the Sponsor is involved. I will immediately disclose it in writing to the 
Sponsor if any person who is involved in the clinical trial is debarred, or if any proceeding for 
debarment is pending, or, to the best of my knowledge, threatened. 
I will not disclose confidential information contained in this document including participant 
information, to anyone other than the recipient study staff and members of the IRB/IEC. I agree 
to ensure that this information will not be used for any purpose other than the evaluation or 
conduct of the clinical investigation without the prior written consent from ModernaTX, Inc. I 
will not disclose information regarding this clinical investigation or publish results of the 
investigation without authorization from ModernaTX, Inc. 
The signature below provides the necessary assurance that this clinical trial will be conducted 
according to all stipulations of the protocol, including statements regarding confidentiality, and 
according to local legal and regulatory requirements, regulations, and ICH E6(R2) GCP 
guidelines. 
Signature of Principal Investigator 
 
 
Date 
 
 
 
 
Printed Name of Principal Investigator  
 
 
 

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PROTOCOL AMENDMENT SUMMARY OF CHANGES TABLE  
DOCUMENT HISTORY 
Document 
Date 
Amendment 2 
14 Mar 2024 
Amendment 1 
16 Jan 2024 
Original Protocol 
08 Feb 2023 
Amendment 2, 14 Mar 2024: Current Amendment 
This amendment is considered to be non-substantial because it neither impacts the safety or 
physical/mental integrity of participants nor the scientific value of the study. 
Overall Rationale for the Amendment: 
The purpose of this amendment is to provide clarifications as outlined in the table below. 
The summary of changes table provided here describes the major changes made in Amendment 2 
relative to Amendment 1, including the sections modified and the corresponding rationales. As 
applicable, the synopsis of Amendment 2 has been modified to correspond to changes in the 
body of the protocol. Additionally, minor inconsistences have been corrected. 
Summary of Major Changes from Protocol Amendment 1 to Protocol Amendment 2: 
Section # and Name 
Description of Change 
Brief Rationale 
2.1.1 Risk Assessment 
Updated Text 
To align with the Company 
Core Data Sheet 
5.2.2 Exclusion Criteria 
Criterion 1 was changed to ‘Participants 
who enrolled in Part 1 of the mRNA-
1083-P101 (Phase 1/2) study’ 
To clarify that participants 
from Part 1 were excluded 
 
 
In Criterion 11, ‘Participants whose 
values have not returned to Baseline 
after their convalescent period will also 
be excluded.’ was removed. 
To remove redundancy 
 
Criterion 23 was changed to ‘Unaware 
whether they received an influenza 
vaccine during or since September 
2023’ 
To reflect the most recent 
influenza season 
6.10.1 Prior Medications 
The following was added: ‘Any 
seasonal influenza vaccine administered 
during or since September 2023 (for 
Part 2 of the study)’  
To specify the most recent 
influenza season for Part 2 of 
the study 
 
10.5.1 Internal Safety Team 
The following was added, ‘In Part 2 of 
the study, there will be no scheduled 
IST review. An ad-hoc IST review may 
occur as outlined by the IST charter’ 
To clarify the role of the IST 
in Part 2 of the study 

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TABLE OF CONTENTS 
CLINICAL STUDY PROTOCOL ..................................................................................................1 
DECLARATION OF INVESTIGATOR .........................................................................................2 
PROTOCOL AMENDMENT SUMMARY OF CHANGES TABLE ............................................3 
LIST OF ABBREVIATIONS ........................................................................................................10 
1. 
PROTOCOL SUMMARY ..........................................................................................13 
1.1. 
Protocol Synopsis .......................................................................................................13 
1.2. 
Schema ........................................................................................................................19 
1.3. 
Schedule of Activities (SoA) ......................................................................................21 
2. 
INTRODUCTION ......................................................................................................27 
2.1. 
Benefit/Risk Assessment ............................................................................................33 
2.1.1. 
Risk Assessment .........................................................................................................33 
2.1.2. 
Benefit Assessment .....................................................................................................35 
2.1.3. 
Overall Benefit/Risk Conclusion ................................................................................35 
3. 
OBJECTIVES AND ENDPOINTS ............................................................................37 
3.1. 
Part 1 ...........................................................................................................................37 
3.2. 
Part 2 ...........................................................................................................................38 
4. 
STUDY DESIGN .......................................................................................................40 
4.1. 
Overall Design ............................................................................................................40 
4.2. 
Scientific Rationale for Study Design ........................................................................40 
4.3. 
Justification for Dose ..................................................................................................41 
4.4. 
End of Study Definition ..............................................................................................41 
5. 
STUDY POPULATION .............................................................................................42 
5.1. 
Part 1 (Phase 1/2) ........................................................................................................42 
5.1.1. 
Inclusion Criteria ........................................................................................................42 
5.1.2. 
Exclusion Criteria .......................................................................................................43 
5.2. 
Part 2 (Phase 2 Extension) ..........................................................................................44 
5.2.1. 
Inclusion Criteria ........................................................................................................44 
5.2.2. 
Exclusion Criteria .......................................................................................................45 
5.3. 
Lifestyle Restrictions ..................................................................................................47 
5.4. 
Screen Failures ............................................................................................................47 
6. 
STUDY INTERVENTION(S) AND CONCOMITANT THERAPY ........................49 

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6.1. 
Study Intervention(s) Administered ...........................................................................49 
6.1.1. 
Part 1 (Phase 1/2) ........................................................................................................49 
6.1.2. 
Part 2 (Phase 2 - Extension) ........................................................................................50 
6.2. 
Preparation, Handling, Storage, and Accountability ..................................................51 
6.2.1. 
Preparation of Study Injection ....................................................................................51 
6.2.2. 
Clinical Study Material Packaging and Labeling .......................................................51 
6.2.3. 
Clinical Study Material Storage ..................................................................................51 
6.2.4. 
Clinical Study Material Accountability ......................................................................51 
6.2.5. 
Clinical Study Material Handling and Disposal .........................................................52 
6.3. 
Assignment to Study Intervention ..............................................................................52 
6.4. 
Blinding ......................................................................................................................52 
6.5. 
Study Intervention Compliance ..................................................................................52 
6.6. 
Dose Modification ......................................................................................................53 
6.7. 
Criteria for Temporarily Delaying Study Vaccination ...............................................53 
6.8. 
Treatment of Overdose ...............................................................................................53 
6.9. 
Continued Access to Study Investigational Product After the End of the 
Study ...........................................................................................................................53 
6.10. 
Prior and Concomitant Therapy ..................................................................................54 
6.10.1. 
Prior Medications ........................................................................................................54 
6.10.2. 
Concomitant Medications and Therapies ...................................................................54 
6.10.3. 
Prohibited Therapy .....................................................................................................55 
7. 
DELAY OR DISCONTINUATION OF STUDY INTERVENTION AND 
PARTICIPANT DISCONTINUATION/WITHDRAWAL .......................................56 
7.1. 
Pause Rules .................................................................................................................56 
7.2. 
Discontinuation of Study Intervention........................................................................57 
7.3. 
Lost to Follow-Up.......................................................................................................58 
8. 
STUDY ASSESSMENTS AND PROCEDURES ......................................................59 
8.1. 
Demography ...............................................................................................................60 
8.2. 
Immunogenicity Assessments ....................................................................................60 
8.2.1. 
Part 1 (Phase 1/2) ........................................................................................................60 
8.2.2. 
Part 2 (Phase 2 Extension) ..........................................................................................60 
8.3. 
Safety Assessments .....................................................................................................60 
8.3.1. 
Part 1 (Phase 1/2) ........................................................................................................60 

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8.3.2. 
Part 2 (Phase 2 Extension) ..........................................................................................61 
8.3.3. 
Physical Examinations (Part 1 and Part 2) .................................................................62 
8.3.4. 
Vital Signs (Part 1 and Part 2) ....................................................................................62 
8.3.5. 
Electrocardiograms (Part 1 and Part 2) .......................................................................63 
8.3.6. 
Clinical Safety Laboratory Tests (Part 1) ...................................................................63 
8.3.7. 
Assessment for Respiratory Viral Infection ...............................................................63 
8.3.7.1. 
Part 1 (Phase 1/2) ........................................................................................................63 
8.3.7.2. 
Part 2 (Phase 2 Extension) ..........................................................................................64 
8.3.8. 
Pregnancy Testing (Part 1 and Part 2) ........................................................................64 
8.3.9. 
Safety Telephone Calls (Part 1 and Part 2) .................................................................64 
8.3.10. 
Electronic Diaries (Part 1 and Part 2) .........................................................................64 
8.4. 
Adverse Events, Serious Adverse Events, and Other Safety Reporting .....................65 
8.4.1. 
Time Period and Frequency for Collecting AE and SAE Information .......................66 
8.4.2. 
Method of Detecting AEs and SAEs ..........................................................................66 
8.4.3. 
Eliciting and Documenting Adverse Events ...............................................................67 
8.4.4. 
Regulatory Reporting Requirements for SAEs ...........................................................67 
8.4.5. 
Pregnancy ...................................................................................................................68 
8.5. 
Pharmacokinetics ........................................................................................................68 
8.6. 
Pharmacodynamics .....................................................................................................68 
8.7. 
Genetics ......................................................................................................................68 
8.8. 
Biomarkers ..................................................................................................................68 
8.9. 
Health Economics or Medical Resource Utilization and Health Economics .............69 
9. 
STATISTICAL CONSIDERATIONS .......................................................................70 
9.1. 
Blinding and Responsibility for Analyses ..................................................................70 
9.2. 
Statistical Hypotheses .................................................................................................71 
9.3. 
Sample Size Determination ........................................................................................71 
9.3.1. 
Part 1 ...........................................................................................................................71 
9.3.2. 
Part 2 ...........................................................................................................................71 
9.4. 
Analysis Sets ...............................................................................................................72 
9.5. 
Statistical Analyses .....................................................................................................72 
9.5.1. 
Immunogenicity Analyses ..........................................................................................72 
9.5.2. 
Efficacy Analyses (Part 1 Only) .................................................................................73 
9.5.3. 
Safety Analyses ..........................................................................................................73 

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9.5.4. 
Exploratory Analyses ..................................................................................................74 
9.6. 
Planned Analyses ........................................................................................................74 
9.6.1. 
Multiplicity .................................................................................................................75 
10. 
SUPPORTING DOCUMENTATION AND OPERATIONAL 
CONSIDERATIONS ..................................................................................................76 
10.1. 
Appendix 1: Regulatory, Ethical, and Study Oversight Considerations ....................76 
10.1.1. 
Regulatory and Ethical Considerations ......................................................................76 
10.1.2. 
Audits and Inspections ................................................................................................76 
10.1.3. 
Financial Disclosure ...................................................................................................77 
10.1.4. 
Informed Consent Process ..........................................................................................77 
10.1.5. 
Protocol Amendments ................................................................................................78 
10.1.6. 
Protocol Deviations ....................................................................................................78 
10.1.7. 
Recruitment Strategy ..................................................................................................79 
10.1.8. 
Data Protection ...........................................................................................................79 
10.1.9. 
Sample Retention and Future Biomedical Research ..................................................80 
10.1.10. 
Dissemination of Clinical Study Data ........................................................................80 
10.1.11. 
Data Quality Assurance ..............................................................................................80 
10.1.12. 
Data Collection and Management ..............................................................................81 
10.1.13. 
Source Documents ......................................................................................................81 
10.1.14. 
Study and Site Start and Closure ................................................................................82 
10.1.15. 
Publication Policy .......................................................................................................82 
10.2. 
Appendix 2: Clinical Laboratory Tests .......................................................................84 
10.3. 
Appendix 3: AEs and SAEs: Definitions and Procedures for Recording, 
Evaluating, Follow-up, and Reporting ........................................................................85 
10.3.1. 
Definition of AE .........................................................................................................85 
10.3.2. 
Definition of Serious Adverse Events ........................................................................85 
10.3.3. 
Solicited Adverse Reactions .......................................................................................86 
10.3.4. 
Definition of Unsolicited Adverse Events ..................................................................88 
10.3.5. 
Medically Attended Adverse Events ..........................................................................89 
10.3.6. 
Adverse Events of Special Interest .............................................................................89 
10.3.6.1. 
Anaphylaxis ................................................................................................................89 
10.3.6.2. 
Myocarditis/Pericarditis/Myopericarditis ...................................................................90 
10.3.7. 
Influenza-Like Illness .................................................................................................91 

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10.3.8. 
Suspicion of SARS-CoV-2 Infection ..........................................................................91 
10.3.9. 
Recording and Follow-Up of AE and/or SAE ............................................................92 
10.3.9.1. 
Assessment of Intensity ..............................................................................................92 
10.3.9.2. 
Assessment of Causality .............................................................................................93 
10.3.10. 
Reporting of SAEs ......................................................................................................93 
10.4. 
Appendix 4: Adverse Events of Special Interest ........................................................95 
10.5. 
Appendix 5: Safety Oversight and Committees Structure ..........................................97 
10.5.1. 
Internal Safety Team ...................................................................................................97 
10.5.2. 
Cardiac Event Adjudication Committee .....................................................................98 
10.6. 
Appendix 6: Contraceptive and Barrier Guidance ......................................................99 
10.7. 
Appendix 7: CDC Case Definitions of Probable and Confirmed Myocarditis, 
Pericarditis, and Myopericarditis ..............................................................................102 
10.8. 
Appendix 8: Protocol Amendment History ..............................................................104 
11. 
REFERENCES .........................................................................................................107 
 
 
 

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LIST OF TABLES  
Table 1: 
Schedule of Activities (Part 1 – Phase 1/2) ................................................................21 
Table 2: 
Schedule of Activities (Part 2 – Phase 2 Extension) ..................................................24 
Table 3: 
mRNA Vaccines in mRNA-1083-P101(Part 1) .........................................................29 
Table 4: 
mRNA Vaccines in mRNA-1083-P101(Part 2) .........................................................30 
Table 5: 
Study Arm(s) and Interventions (Part 1 – Phase 1/2) .................................................49 
Table 6: 
Study Arm(s) and Interventions (Part 2 – Phase 2 Extension) ...................................50 
Table 7: 
Pause Rule Criteria, Events, and Thresholds ..............................................................56 
Table 8: 
Probability of AEs Based on Sample Size(Part 1) ......................................................71 
Table 9: 
Probability of AEs Based on Sample Size (Part 2) .....................................................71 
Table 10: Populations for Analyses ............................................................................................72 
Table 11: Analysis Strategy for Safety Parameters ....................................................................74 
Table 12: Protocol-required Safety Laboratory Tests (Part 1) ....................................................84 
Table 13: Solicited Adverse Reactions and Grades ....................................................................87 
Table 14: Adverse Events of Special Interest .............................................................................95 
Table 15: CDC Case Definitions of Probable and Confirmed Myocarditis, Pericarditis, 
and Myopericarditis ..................................................................................................102 
 
LIST OF FIGURES  
No table of figures entries found.  
 
 
 

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LIST OF ABBREVIATIONS  
Abbreviation 
Definition 
AE 
Adverse event 
AESI 
Adverse event of special interest 
ALT 
Alanine aminotransferase 
AR 
Adverse reaction 
AST 
Aspartate aminotransferase 
BLA 
Biologics License Application 
BMI 
Body mass index 
CDC 
Centers for Disease Control and Prevention 
CEAC 
Cardiac Event Adjudication Committee 
CFR 
Code of Federal Regulations 
CI 
Confidence interval 
COVID-19 
Coronavirus disease 2019 
CRF 
Case report form 
CRO 
Clinical research organization 
CSR 
Clinical study report 
CTFG 
Clinical trial facilitation group 
DHHS 
Department of Health and Human Services 
DRESS 
Drug reaction with eosinophilia and systemic symptoms 
DSPC 
1,2-distearoyl-sn-glycero-3-phosphocholine 
ECG/EKG 
Electrocardiogram 
eCRF 
Electronic case report form 
EDC 
Electronic data capture 
eDiary 
Electronic diary 
EoS 
End of study 
EUA 
Emergency Use Authorization 
FAS 
Full analysis set 
FDA 
Food and Drug Administration 
FSH 
Follicle-stimulating hormone 

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Abbreviation 
Definition 
GCP 
Good Clinical Practice 
GGT 
Gamma-glutamyl transferase 
GMFR 
Geometric mean fold rise 
GMT 
Geometric mean titer 
HA 
Hemagglutinin 
HAI 
Hemagglutination inhibition 
HCP 
Healthcare professional 
HD 
High dose 
HELLP 
Hemolysis, elevated liver enzymes, and low platelets 
HIV 
Human immunodeficiency virus 
HRT 
Hormonal replacement therapy 
IB 
Investigator’s Brochure 
ICF 
Informed consent form 
ICH 
International Council for Harmonisation 
IEC 
Independent ethics committee 
ILI 
Influenza-like illness 
IM 
Intramuscular(ly) 
IP 
Investigational product 
IRB 
Institutional review board 
IRT 
Interactive response technology 
IST 
Internal safety team 
LAM 
Lactational amenorrhea method 
LLOQ 
Lower limit of quantification 
LNP 
Lipid nanoparticle 
LTFU 
Lost to follow-up 
MAAE 
Medically attended adverse event 
MedDRA 
Medical Dictionary for Regulatory Activities 
mRNA 
Messenger ribonucleic acid 
NA 
Not applicable 

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Abbreviation 
Definition 
nAb 
Neutralizing antibody 
NH 
Northern Hemisphere 
NI 
Noninferiority 
NIM 
Noninferiority margin 
NP 
Nasopharyngeal 
NTD 
N-terminal domain 
PEG2000-DMG 
1-monomethoxypolyethyleneglycol-2,3-dimyristylglycerol 
with polyethylene glycol of average molecular weight 2000 
POCBP 
Participant(s) of childbearing potential 
PP 
Per protocol 
PsVNA 
Pseudovirus neutralization assay 
PT 
Preferred term 
RBD 
Receptor-binding domain 
RT-PCR 
Reverse transcription polymerase chain reaction 
SAE 
Serious adverse event 
SAP 
Statistical analysis plan 
SARS-CoV-2 
Severe acute respiratory syndrome coronavirus 2 
SH 
Southern Hemisphere 
SoA 
Schedule of Activities 
SOC 
System organ class 
Tris 
tris(hydroxymethyl) aminomethane 
ULN 
Upper limit of normal 
US 
United States 
USP 
United States Pharmacopoeia 
WHO 
World Health Organization 
 

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1. 
PROTOCOL SUMMARY  
1.1. 
Protocol Synopsis  
Protocol Title: 
A Phase 1/2, Randomized, Observer-blind, Active-Control Study to Evaluate the Safety, 
Reactogenicity, and Immunogenicity of mRNA-based Influenza and SARS-CoV-2 
Multi-component Vaccines in Healthy Adults 
Brief Title: 
A clinical trial to investigate how safe a new SARS-CoV-2 and influenza vaccine (mRNA-1083) 
is and whether it helps the immune system fight viruses in healthy adult participants 
Regulatory Agency Identifier Number(s): 
IND: 
29324 
Rationale: 
The Sponsor is developing mRNA-1083, a lipid-encapsulated messenger ribonucleic acid 
(mRNA)-based prophylactic combination vaccine encoding influenza and severe acute 
respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens. mRNA-1083 contains 5 to 6 
mRNAs: 4 sequences encoding surface glycoprotein hemagglutinin (HA) of seasonal influenza 
viruses and 1 to 2 sequences encoding linked N-terminal domain (NTD) and receptor-binding 
domain (RBD) of SARS-CoV-2 spike proteins. mRNA-1083 encodes the respective antigens 
also encoded by mRNA-1010 (seasonal influenza) and mRNA-1283 (SARS-CoV-2). 
The administration of the mRNA-1083 vaccine has the potential to efficiently reduce the overall 
burden of acute viral respiratory diseases by providing simultaneous protection against influenza 
and SARS-CoV-2 viruses in a convenient dosing regimen. mRNA-1083 offers greater 
convenience and has the potential to lead to increased compliance with vaccine 
recommendations, an approach which has been frequently used for pediatric vaccines 
(Kurosky et al 2017). Furthermore, this combined regimen could provide a public health benefit 
through synergistically increasing coverage rates against influenza and SARS-CoV-2 viruses. 
This Phase 1/2 clinical trial aims to generate safety, reactogenicity, and immunogenicity data of 
multi-component influenza and SARS-CoV-2 vaccine in adults ≥18 to <80 years of age. Multiple 
compositions and dose levels will be evaluated. 
The study is divided into 2 parts: Part 1 and Part 2. Part 1 (Phase 1/2) includes adults who are 18 
to <80 years and Part 2 (Phase 2 Extension) includes adults who are 18 to <50 years. 

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Objectives and Endpoints: 
The objectives and endpoints for the Part 1 (Phase 1/2) of the study are presented in the table 
below: 
Objectives 
Endpoints 
Primary 
To evaluate the safety and reactogenicity of study 
intervention administration across study treatment 
arms 
• 
Solicited local and systemic ARs through 
7 days after injection 
• 
Unsolicited AEs through 28 days after 
injection 
• 
Unsolicited Severe AEs through 28 days after 
injection 
• 
Unsolicited MAAEs from Day 1 to 
Day 181/EoS 
• 
Unsolicited AESIs from Day 1 to 
Day 181/EoS 
• 
SAEs from Day 1 to Day 181/EoS 
• 
Unsolicited AEs leading to discontinuation 
from Day 1 to Day 181/EoS 
Secondary 
To evaluate the humoral immune responses to 
vaccine-matched strains for influenza and 
SARS-CoV-2 across study treatment arms at 
Day 29 
• 
GMT and GMFR at Day 29 compared to 
Day 1 by HAI assay for influenza and by 
PsVNA for SARS-CoV-2 
• 
Influenza: Percentage of participants with 
seroconversion, defined as a Day 29 titer 
 if Baseline is 
 or a 4-fold or 
greater rise if Baseline is 
 in anti-HA 
antibodies measured by HAI assay 
• 
SARS-CoV-2: Percentage of participants 
with seroresponse, defined as a Day 29 titer 
≥4-fold if Baseline is ≥LLOQ or ≥4 × LLOQ 
if Baseline titer is <LLOQ in nAb titers 
measured by PsVNA 
To evaluate the humoral immune responses to 
vaccine-matched strains for influenza and 
SARS-CoV-2 across study treatment arms at all 
evaluable humoral immunogenicity time points 
• 
GMT and GMFR at all evaluable time points 
compared to Day 1 by HAI for influenza and 
PsVNA for SARS-CoV-2 
• 
Influenza: Percentage of participants with 
seroconversion, as defined above 
• 
SARS-CoV-2: Percentage of participants 
with seroresponse, as defined above 
CCI
CCI
CCI

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Objectives 
Endpoints 
Exploratory (may be performed) 
To evaluate the humoral immune responses to 
vaccine-mismatched strains for influenza and 
SARS-CoV-2 across study treatment arms 
• 
GMT and GMFR at all evaluable time points 
compared to Day 1 by HAI for influenza and 
PsVNA for SARS-CoV-2 
• 
Influenza: Percentage of participants with 
seroconversion, as defined above 
• 
SARS-CoV-2: Percentage of participants 
with seroresponse, as defined above 
To evaluate the humoral immune responses 
against vaccine-matched and vaccine-mismatched 
strains for influenza and SARS-CoV-2 across 
study treatment arms 
• 
GMT and GMFR at all evaluable time points 
compared to Day 1 by alternative methods, 
including, but not limited to: 
microneutralization assay for influenza or 
ligand-binding assay for SARS-CoV-2 
To evaluate the cellular immune responses against 
influenza and SARS-CoV-2 in a subset of 
participants 
• 
Frequency, magnitude, and phenotype of 
virus-specific T-cell and B-cell responses 
measured by flow cytometry or other 
methods 
• 
Perform targeted repertoire analysis of 
B-cells and T-cells after injection 
To further characterize the immune response to 
influenza and SARS-CoV-2 across study 
treatment arms 
• 
Frequency, specificities, or other endpoints to 
be determined for the further characterization 
of immune responses 
To assess the occurrence of clinical influenza and 
COVID-19 in study participants and characterize 
their immune response to infection and viral 
isolates 
• 
Frequency of RT-PCR-confirmed clinical 
influenza and COVID-19 
• 
Assessment of immune responses to infection 
and viral isolates 
Abbreviations: AE = adverse event; AR = adverse reaction; COVID-19 = coronavirus disease 2019; EoS = end of 
study; GMFR = geometric mean fold rise; GMT = geometric mean titer; HA = hemagglutination; 
HAI = hemagglutination inhibition; LLOQ = lower limit of quantification; MAAE = medically attended adverse 
event; nAb = neutralizing antibody; PsVNA = pseudovirus neutralization assay; RT-PCR = reverse transcription 
polymerase chain reaction; SAR-CoV-2 = severe acute respiratory syndrome coronavirus 2. 
The objectives and endpoints for the Part 2 (Phase 2 Extension) of the study are presented below: 
Objectives 
Endpoints 
Primary 
To evaluate the safety and reactogenicity of study 
intervention administration across study treatment 
arms 
• 
Solicited local and systemic ARs through 7 days 
after injection 
• 
Unsolicited AEs through 28 days after injection 
• 
Unsolicited Severe AEs through 28 days after 
injection 
• 
Unsolicited MAAEs from Day 1 to 
Day 181/EoS 
• 
Unsolicited AESIs from Day 1 to Day 181/EoS 
• 
SAEs from Day 1 to Day 181/EoS 
• 
Unsolicited AEs leading to discontinuation from 
Day 1 to Day 181/EoS 

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Objectives 
Endpoints 
To evaluate the humoral immune responses to 
vaccine-matched strains for influenza and 
SARS-CoV-2 across study treatment arms at 
Day 29  
• GMT and GMFR at Day 29 compared to 
Day 1 by HAI assay for influenza and by 
PsVNA for SARS-CoV-2 
• Influenza: Percentage of participants with 
seroconversion, defined as a Day 29 titer 
 if Baseline is 
 or a 4-fold or 
greater rise if Baseline is 
 in anti-HA 
antibodies measured by HAI assay 
• SARS-CoV-2: Percentage of participants 
with seroresponse, defined as a Day 29 titer 
≥4-fold if Baseline is ≥LLOQ or ≥4 × 
LLOQ if Baseline titer is <LLOQ in nAb 
titers measured by PsVNA 
Secondary 
To evaluate the humoral immune responses to 
vaccine-matched strains for influenza and 
SARS-CoV-2 across study treatment arms at 
all evaluable humoral immunogenicity time 
points 
• 
GMT and GMFR at all evaluable time points 
compared to Day 1 by HAI for influenza and 
PsVNA for SARS-CoV-2 
• 
Influenza: Percentage of participants with 
seroconversion, as defined above 
• 
SARS-CoV-2: Percentage of participants with 
seroresponse, as defined above 
Exploratory (may be performed) 
 
To evaluate the humoral immune responses to 
vaccine-mismatched strains for influenza and 
SARS-CoV-2 across study treatment arms 
• 
GMT and GMFR at all evaluable time points 
compared to Day 1 by HAI for influenza and 
PsVNA for SARS-CoV-2 
• 
Influenza: Percentage of participants with 
seroconversion, as defined above 
• 
SARS-CoV-2: Percentage of participants with 
seroresponse, as defined above 
To evaluate the humoral immune responses 
against vaccine-matched and vaccine-mismatched 
strains for influenza and SARS-CoV-2 across 
study treatment arms 
• 
GMT and GMFR at all evaluable time points 
compared to Day 1 by alternative methods, 
including, but not limited to: microneutralization 
assay for influenza or ligand-binding assay for 
SARS-CoV-2 
To further characterize the immune response to 
influenza and SARS-CoV-2 across study 
treatment arms 
• 
Frequency, specificities, or other endpoints to be 
determined for the further characterization of 
immune responses 
Abbreviations: AE = adverse event; AR = adverse reaction; COVID-19 = coronavirus disease 2019; EoS = end of 
study; GMFR = geometric mean fold rise; GMT = geometric mean titer; HA = hemagglutination; 
HAI = hemagglutination inhibition; LLOQ = lower limit of quantification; MAAE = medically attended adverse 
event; nAb = neutralizing antibody; PsVNA = pseudovirus neutralization assay; RT-PCR = reverse transcription 
polymerase chain reaction; SAR-CoV-2 = severe acute respiratory syndrome coronavirus 2. 
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Overall Design: 
The study is divided into 2 Parts: 
Part 1 of the study will be a Phase 1/2 randomized, stratified, observer-blind, active-control 
study and will evaluate the safety, reactogenicity, and immunogenicity of mRNA-1083 
compositions and dose levels compared to active-control experimental injections mRNA-1010, 
mRNA-1283.222, mRNA-1273.222, and licensed active-control vaccines, Fluarix and Fluzone 
HD (Cohort A only) in healthy adults ≥18 to <80 years of age (Cohort A is in adults ≥65 to 
<80 years of age and Cohort B is in adults ≥18 to <65 years of age). 
Part 2 of the study will be a Phase 2 randomized, stratified, observer-blind, active-control study 
to evaluate the safety, reactogenicity, and immunogenicity of mRNA-1083 compositions and 
dose levels compared with active-control vaccines mRNA-1010, mRNA-1283.815, 
mRNA-1273.815, and licensed active-control vaccine, Fluarix in healthy adults ≥18 to <50 years 
of age. 
Brief Summary: 
The study will be performed in 2 parts, and results for each part of the study will be provided as 
a separate clinical study report. 
Part 1: The purpose of this Phase 1/2 clinical trial is to generate sufficient safety, reactogenicity, 
and immunogenicity data to enable selection of an mRNA-1083 vaccine composition and dose 
level to evaluate in a subsequent Phase 3 clinical trial in adults. 
Study details include: 
• Study duration: approximately up to 7 months, including the Screening period. 
• Treatment duration: Study interventions are scheduled for all participants on Day 1 
(Baseline). 
• Visit frequency: All participants will have up to 5 in-person visits (Days 0 [Eligibility 
Visit], 1 [Baseline], 8, 29, 181, and unscheduled visits if appropriate) and 4 safety 
follow-up calls (Days 57, 91, 121, and 151). 
Part 2: The purpose of this Phase 2 Extension clinical trial is to generate safety and 
immunogenicity data for additional mRNA-1083 compositions and dose levels in young adults 
≥18 years and <50 years of age. 
Study Details: 
• Study duration: approximately up to 7 months, including the Screening period. 
• Treatment duration: Study interventions are scheduled for all participants on Day 1 
(Baseline). 
• Visit frequency: All participants will have up to 4 in-person visits (Screening, Day 1, 
Day 29 and Day 181 and unscheduled visits if appropriate) and 3 safety follow-up 
calls (Days 8, 91, and 151). 

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Number of Participants: 
Approximately 1744 participants will enroll in the overall clinical trial, with approximately 1224 
participants in Part 1 and approximately 520 participants in Part 2. 
Note: Enrolled means participants’ agreement to participate in a clinical study following 
completion of the informed consent process and Screening. Potential participants who are 
screened for the purpose of determining eligibility for the clinical trial, but do not participate in 
the clinical trial, are not considered enrolled, unless otherwise specified by the protocol. A 
participant will be considered enrolled if the informed consent is not withdrawn prior to 
participating in any clinical trial activity after Screening. 
Study Cohorts and Duration: 
Part 1: This part of the clinical trial will enroll approximately 1224 participants into 1 of 2 age 
cohorts: Cohort A for participants ≥65 to <80 years of age (approximately 600 participants) or 
Cohort B for participants ≥18 to <65 years of age (approximately 624 participants). In Cohort A, 
approximately 600 participants will be randomized (in equal allocation ratio) into the 
investigational treatment arms, stratified by influenza vaccine status in the most recent influenza 
season (received or not received since Sept 2022). In Cohort B, approximately 624 participants 
will be randomized (in equal allocation ratio) into the investigational treatment arms, stratified 
by the 2 age groups, ≥18 to <50 years and ≥50 to <65 years, and by influenza vaccine status in 
the most recent influenza season (received or not received since Sep 2022). Approximately 50% 
of the participants in Cohort B will be ≥50 to <65 years of age. 
Part 2: This part of the clinical trial will enroll approximately 520 participants ≥18 to <50 years 
of age. Participants will be randomized (in equal allocation ratio) into the investigational 
treatment arms, stratified by influenza vaccine status in the most recent influenza season 
(received or not received since Sep 2023). 
All participants will have follow-up visits for 6 months after the study intervention 
administration. 

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1.2. 
Schema  
Part 1: 
 
Abbreviations: HD = high dose; mRNA = messenger ribonucleic acid 
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Part 2: 
 
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1.3. 
Schedule of Activities (SoA)  
Table 1: 
Schedule of Activities (Part 1 – Phase 1/2)  
Visit Number 
SCRN 
1 
2 
3 
4, 5, 6, 7 
8 
USV 
Type of Visit 
C 
C 
C 
C 
SC 
C 
C 
Month Timepoint 
NA 
 
 
M1 
M2-M5 
M6 
Up to M6 
Visit Day 
SCRNa 
D1 
(Baseline)a 
D8 
D29 
D57, D91, 
D121, D151 
D181/ 
EoS 
NA 
Window Allowance (Days) 
-28 
NA 
-1 to +3 
-7 to +3 
±5 
±14 
NA 
Informed consent form, demographics, concomitant 
medications, medical history 
X 
 
 
 
 
 
 
Inclusion/exclusion criteria 
X 
X 
 
 
 
 
 
Blood collection for safety laboratory samplesb 
X 
 
X 
 
 
 
 
Full physical examinationc 
X 
 
 
 
 
 
 
Axillary lymph nodes assessmentd 
 
X 
 
 
 
 
 
Symptom-directed physical examinatione 
 
X 
X 
X 
 
X 
X 
Vital sign measurementsf 
X 
X 
 
 
 
 
 
Electrocardiogramg 
 
X 
 
 
 
 
 
Pregnancy testingh 
X 
X 
 
 
 
 
 
Randomization 
 
X 
 
 
 
 
 
Study intervention (including 60-minute, postdose 
observation period) 
 
X 
 
 
 
 
 
Blood collection for humoral immunogenicityi 
 
X 
 
X 
 
X 
 
Blood collection for cellular immunogenicityi 
 
X 
 
X 
 
 
 
Optional blood collection for genomicsj 
 
X 
 
 
 
 
 
Optional blood collection for transcriptomicsj 
 
X 
X 
X 
 
 
 
Blood sample for potential cardiac biomarker 
analysisk 
 
X 
 
 
 
 
 
Nasal swab for virus detectionl 
 
X 
 
 
 
 
X 

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Visit Number 
SCRN 
1 
2 
3 
4, 5, 6, 7 
8 
USV 
Type of Visit 
C 
C 
C 
C 
SC 
C 
C 
Month Timepoint 
NA 
 
 
M1 
M2-M5 
M6 
Up to M6 
Visit Day 
SCRNa 
D1 
(Baseline)a 
D8 
D29 
D57, D91, 
D121, D151 
D181/ 
EoS 
NA 
Window Allowance (Days) 
-28 
NA 
-1 to +3 
-7 to +3 
±5 
±14 
NA 
Blood collection for SARS-CoV-2 antibodies, 
nucleocapsid 
 
X 
 
 
eDiary activation for recording solicited local and 
systemic ARs (7 days)m 
 
X 
 
 
 
 
 
Review of solicited AR eDiary 
 
 
X 
 
 
 
 
Follow-up safety calln  
 
 
 
 
X 
 
 
Recording of unsolicited AEs through Day 29 
 
X 
X 
X 
 
 
 
Recording of SAEs, AESIs, MAAEs, AEs leading 
to discontinuation, and concomitant medications 
associated with these events 
 
X 
X 
X 
X 
X 
X 
Recording of nonstudy vaccinations 
X 
X 
X 
X 
X 
X 
X 
Study completion 
 
 
 
 
 
X 
 
Abbreviations: AE = adverse event; AESI = adverse event of special interest; AR = adverse reaction; C = clinic visit; COVID-19 = coronavirus disease 2019; 
D = day; ECG = electrocardiogram; EoS = end of study; ILI = influenza-like illness; IM = intramuscular; M = month; MAAE = medically attended adverse 
event; NA = not applicable; SAE = serious adverse event; SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2; SC = safety (telephone) call; 
SCRN = Screening; USV = unscheduled visit;. 
a. 
Screening and Day 1 will NOT be performed on the same day. Additionally, the Screening Visit may be performed over multiple visits within the 28-day 
Screening window. 
b. 
Safety laboratory tests (see Section 10.2) will consist of total white blood cell count, hemoglobin, hematocrit, platelets, aspartate aminotransferase, alanine 
aminotransferase, creatinine, alkaline phosphatase, and total bilirubin. Safety laboratory tests will be performed by the central laboratory. 
c. 
A full physical examination, including height and weight for calculation of body mass index, will be performed at Screening. Additional physical 
examinations may be performed during the study at the discretion of the Investigator. 
d. 
On the day of study intervention administration, prior to injection, axillary lymph nodes of the injection arm will be examined, and any abnormalities will be 
documented. 
e. 
Symptom-directed physical examinations will be performed at all clinic visits, except at Screening, where a full physical examination will be performed. 
Interim physical examinations will be performed at the discretion of the Investigator. Any clinically significant finding identified by a healthcare 
professional during postinjection study visits should be reported as an AE. 

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f. 
Vital sign measurements: Systolic and diastolic blood pressure, heart rate, respiratory rate, and body temperature. The preferred route of temperature 
assessment is oral. Vital signs must be collected at Screening and on the day of injection (Day 1), once before and at least 60 minutes after injection. Vital 
signs may be collected at other clinic visits in conjunction with a symptom-directed physical examination. For all vital sign measurements, participant must 
be seated for 5 minutes before any measurements are taken. 
g. 
For participants ≥18 to <51years of age only: A 12-lead ECG will be obtained, after 10 minutes of supine rest, at Visit 1/Day 1 prior to injection. The 
purpose of the ECG is to serve as a stored Baseline comparison, should it be necessary, for subsequent clinical evaluation if a case of suspected myocarditis 
and/or pericarditis occurs within the conduct of the clinical trial. The ECG output should be filed in the participant’s binder. Central reading of the ECG will 
not be performed. Incidental significant abnormal ECG findings should contribute to the Investigator’s assessment of eligibility, at their discretion, as per 
Exclusion Criterion 3. 
h. 
For participants of childbearing potential, a point-of-care urine pregnancy test will be performed at the Screening Visit and before the IM injections on 
Day 1. At the discretion of the Investigator, a pregnancy test either via blood or point-of-care urine can be performed at any time. For participants of 
nonchildbearing potential, the follicle-stimulating hormone level may be measured at the Screening Visit, as necessary, and at the discretion of the 
Investigator, to confirm menopausal status. 
i. 
Baseline samples for humoral and cellular immunogenicity must be collected prior to receipt of injection on Day 1. Cellular immunogenicity will be sampled 
and assessed in a subset of participants. 
j. 
Transcriptomic and genomic samples will be part of the optional biomarker assessment once consented by the study participant. Blood draws on Day 1 must 
occur prior to participants being administered the study intervention. 
k. 
For participants ≥18 to <51years of age only: Plasma and serum samples will be collected and banked for potential future cardiac biomarker assessment. 
l. 
A nasal swab to test for the presence of viral respiratory pathogens will be collected prior to the study intervention administration on Day 1 to document any 
prevaccination infection. A nasal swab should be collected through study completion for protocol-defined ILI or SARS-CoV-2 ≤7 days of symptom onset. 
m. 
The eDiary activation and entries will be recorded by the participant starting approximately 60 minutes after injection while at the clinic with instruction 
provided by study staff. Study participants will continue to record in the eDiary each day after they leave the clinic, preferably in the evening and at the same 
time each day, on the day of injection and for 6 days following injection. Solicited local and systemic ARs will be recorded separately for each injection site. 
n. 
Trained study staff will call all participants to collect information related to any SAEs, MAAEs, AESIs, AEs leading to study discontinuation, information 
on concomitant medications associated with those events, and any nonstudy vaccinations. 

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Table 2: 
Schedule of Activities (Part 2 – Phase 2 Extension)  
Visit Number 
SCRN 
1 
2 
3 
4, 5 
6 
USV 
Type of Visit 
C 
C 
SC 
C 
SC 
C 
C 
Month Timepoint 
NA 
 
 
M1 
M3-M5 
M6 
Up to M6 
Visit Day 
SCRNa 
D1 
(Baseline)a 
D8 
D29 
D91, D151 
D181/ 
EoS 
NA 
Window Allowance (Days) 
-28 
NA 
-1 to +3 
-7 to +3 
±5 
±14 
NA 
Informed consent form, demographics, concomitant 
medications, medical history 
X 
 
 
 
 
 
 
Inclusion/exclusion criteria 
X 
X 
 
 
 
 
 
Full physical examination b 
X 
 
 
 
 
 
 
Axillary lymph nodes assessment c 
 
X 
 
 
 
 
 
Symptom-directed physical examination d 
 
X 
 
X 
 
X 
X 
Vital sign measurements e 
X 
X 
 
 
 
 
 
Electrocardiogram f 
 
X 
 
 
 
 
 
Pregnancy testing g 
X 
X 
 
 
 
 
 
Randomization 
 
X 
 
 
 
 
 
Study intervention (including 60-minute, postdose 
observation period) 
 
X 
 
 
 
 
 
Blood collection for humoral immunogenicity h 
 
X 
 
X 
 
X 
 
Optional blood collection for genomics i 
 
X 
 
 
 
 
 
Optional blood collection for transcriptomics i 
 
X 
 
X 
 
 
 
Blood sample for potential cardiac biomarker 
analysis j 
 
X 
 
 
 
 
 
Nasal swab for virus detection k 
 
X 
 
 
 
 
 
Blood collection for SARS-CoV-2 antibodies, 
nucleocapsid 
 
X 
 
 
eDiary activation for recording solicited ARs 
(7 days) l 
 
X 
 
 
 
 
 
Review of solicited AR eDiary 
 
 
X 
 
 
 
 

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Visit Number 
SCRN 
1 
2 
3 
4, 5 
6 
USV 
Type of Visit 
C 
C 
SC 
C 
SC 
C 
C 
Month Timepoint 
NA 
 
 
M1 
M3-M5 
M6 
Up to M6 
Visit Day 
SCRNa 
D1 
(Baseline)a 
D8 
D29 
D91, D151 
D181/ 
EoS 
NA 
Window Allowance (Days) 
-28 
NA 
-1 to +3 
-7 to +3 
±5 
±14 
NA 
Follow-up safety call m 
 
 
X 
 
X 
 
 
Recording of unsolicited AEs through Day 29 
 
X 
X 
X 
 
 
 
Recording of SAEs, AESIs, MAAEs, AEs leading 
to discontinuation, and concomitant medications 
associated with these events 
 
X 
X 
X 
X 
X 
X 
Recording of nonstudy vaccinations 
X 
X 
X 
X 
X 
X 
X 
Study completion 
 
 
 
 
 
X 
 
Abbreviations: AE = adverse event; AESI = adverse event of special interest; AR = adverse reaction; BMI = body mass index; C = clinic visit; 
COVID-19 = coronavirus disease 2019; D = day; EoS = end of study; ILI = influenza-like illness; IM = intramuscular; M = month; MAAE = medically 
attended adverse event; NA = not applicable; SAE = serious adverse event; SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2; SC = safety 
(telephone) call; SCRN = Screening; USV = unscheduled visit 
a. 
Screening and Day 1 may be performed on the same day or a different day. Additionally, the Screening Visit may be performed over multiple visits within 
the 28-day Screening window. 
b. 
A full physical examination, including height and weight for calculation of body mass index, will be performed at Screening. Additional physical 
examinations may be performed during the study at the discretion of the Investigator. 
c. 
On the day of study intervention administration, prior to injection, axillary lymph nodes of the injection arm will be examined, and any abnormalities will be 
documented. 
d. 
Symptom-directed physical examinations will be performed at all clinic visits, except at Screening, where a full physical examination will be performed. 
Interim physical examinations will be performed at the discretion of the Investigator. Any clinically significant finding identified by a healthcare 
professional during postinjection study visits should be reported as an AE. 
e. 
Vital sign measurements: Systolic and diastolic blood pressure, heart rate, respiratory rate, and body temperature. The preferred route of temperature 
assessment is oral. Vital signs must be collected at Screening and on the day of injection (Day 1), once before and at least 60 minutes after injection. Vital 
signs may be collected at other clinic visits in conjunction with a symptom-directed physical examination. For all vital sign measurements, participant must 
be seated for 5 minutes before any measurements are taken. 
f. 
A 12-lead ECG will be obtained, after 10 minutes of supine rest, at Visit 1/Day 1 prior to injection. The purpose of the ECG is to serve as a stored Baseline 
comparison, should it be necessary, for subsequent clinical evaluation if a case of suspected myocarditis and/or pericarditis occurs within the conduct of the 
clinical trial. The ECG output should be filed in the participant’s binder. Central reading of the ECG will not be performed. Incidental significant abnormal 
ECG findings should contribute to the Investigator’s assessment of eligibility, at their discretion, as per Exclusion Criterion 3. 

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g. 
For participants of childbearing potential, a point-of-care urine pregnancy test will be performed at the Screening Visit and before the IM injections on 
Day 1. At the discretion of the Investigator, a pregnancy test either via blood or point-of-care urine can be performed at any time. For participants of 
nonchildbearing potential, the follicle-stimulating hormone level may be measured at the Screening Visit, as necessary, and at the discretion of the 
Investigator, to confirm menopausal status. 
h. 
Baseline samples for humoral immunogenicity must be collected prior to receipt of injection on Day 1. 
i. 
Transcriptomic and genomic samples will be part of the optional biomarker assessment once consented by the study participant. Blood draws on Day 1 must 
occur prior to participants being administered the study intervention. 
j. 
Plasma and serum samples will be collected prior to the study intervention administration on Day 1 and banked for potential future cardiac biomarker 
assessment. 
k. 
A nasal swab to test for the presence of viral respiratory pathogens will be collected prior to the study intervention administration on Day 1 to document any 
prevaccination infection. 
l. 
The eDiary activation and entries will be recorded by the participant starting approximately 60 minutes after injection while at the clinic with instruction 
provided by study staff. Study participants will continue to record in the eDiary each day after they leave the clinic, preferably in the evening and at the same 
time each day, on the day of injection and for 6 days following injection. Solicited local and systemic ARs will be recorded separately for each injection site. 
m. 
Trained study staff will call all participants to collect information related to any SAEs, MAAEs, AESIs, AEs leading to study discontinuation, information 
on concomitant medications associated with those events, and any nonstudy vaccinations. 

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2. 
INTRODUCTION  
ModernaTX, Inc. (the Sponsor) is developing lipid nanoparticle (LNP)-mRNA-based 
prophylactic multi-component vaccines (also referred to as combination vaccines) against 
disease associated with respiratory viruses. The mRNA-1083 combination vaccine encodes 
antigens from influenza viruses and SARS-CoV-2 and is intended to prevent disease associated 
with these viruses. 
Seasonal influenza viruses are estimated by the World Health Organization (WHO) to cause 
3 to 5 million cases of severe illness and up to 650,000 deaths each year resulting in a severe 
challenge to public health (WHO 2018). Influenza epidemics occur each year and follow a 
seasonal circulation pattern with increased cases during the winter months in the Northern 
Hemisphere (NH) and Southern Hemisphere (SH) (Riedel et al 2019). Because influenza viruses 
continuously change through a process termed antigenic drift, the circulating viruses are actively 
monitored by a worldwide monitoring network coordinated by the WHO (Monto et al 2015). 
Based on the observed circulation patterns and antigenic changes, an expert panel recommends 
influenza virus strains to be used for vaccine manufacturing twice per year (once for the NH and 
once for the SH). Influenza A and influenza B viruses are the most relevant influenza viruses for 
human infection. Therefore, current vaccine recommendations include 1 influenza A H1N1 
strain, 1 influenza A H3N2 strain, and 2 influenza B strains (covering the B/Victoria and 
B/Yamagata lineages). 
Currently, licensed seasonal influenza virus vaccines rarely exceed 60% overall effectiveness 
and are poorly effective during years when the circulating viruses do not match the strains 
selected for the vaccine antigens (CDC 2020a). Influenza vaccines based on mRNA technology 
could provide several benefits compared to current vaccines, including the ability to respond to 
strain changes more quickly, avoidance of mutations that may be acquired during vaccine 
production in eggs or cell culture, stronger immune responses, as well as improved protection in 
older adults (Rockman et al 2020). 
Coronaviruses are a large family of viruses that cause illness ranging from the common cold to 
more severe diseases, such as Middle East respiratory syndrome and severe acute respiratory 
syndrome. An outbreak of a novel coronavirus (later designated SARS-CoV-2, the causative 
agent of COVID-19) initially emerged in Wuhan, Hubei Province, China in December 2019. The 
WHO declared COVID-19 a pandemic on 11 Mar 2020, and COVID-19 continues to have a 
major global public health impact, with more than 500 million cases and 6.5 million deaths as of 
17 Nov 2022 (WHO 2022). 
The Sponsor has developed a rapid-response, proprietary vaccine platform based on an mRNA 
delivery system. The platform is based on the principle and observations that cells in vivo can 
take up mRNA, translate it, and then express protein viral antigen(s) on the cell surface. The 
delivered mRNA does not enter the cellular nucleus or interact with the genome, is 
nonreplicating, and is expressed transiently. 
The Study Is Divided into 2 Parts: 
Part 1 of the study will be a Phase 1/2 randomized, stratified, observer-blind, active-control 
study and will evaluate the safety, reactogenicity, and immunogenicity of mRNA-1083 
compositions and dose levels compared to active-control experimental injections mRNA-1010, 

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mRNA-1283.222, mRNA-1273.222, and licensed active-control vaccines, Fluarix and Fluzone 
HD (Cohort A only) in healthy adults ≥18 to <80 years of age (Cohort A is in adults ≥65 to 
<80 years of age and Cohort B is in adults ≥18 to <65 years of age). 
Part 2 of the study will be a Phase 2 randomized, stratified, observer-blind, active-control study 
to evaluate the safety, reactogenicity, and immunogenicity of mRNA-1083 compositions and 
dose levels compared with active-control vaccines mRNA-1010, mRNA-1283.815, 
mRNA-1273.815, and licensed active-control vaccine, Fluarix in healthy adults ≥18 to <50 years 
of age. 

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Table 3: 
mRNA Vaccines in mRNA-1083-P101(Part 1)  
Vaccine 
mRNA Encoding Influenza HA 
mRNA Encoding SARS-CoV-2 Spike 
H1N1 H3N2 
B/ 
Yamagata 
B/ 
Victoria 
Wuhan-Hu-1 
RBD-NTD 
BA.4/BA.5 
RBD-NTD 
Wuhan-Hu-1 
full length 
BA.4/BA.5 full 
length 
mRNA-1083.1 
 
 
 
 
 
 
 
 
mRNA-1083.2 
 
 
 
 
 
 
 
 
mRNA-1083.3 
 
 
 
 
 
 
 
 
mRNA-1010  
 
 
 
 
 
 
 
 
mRNA-1283.222 
 
 
 
 
 
 
 
 
mRNA-1273.222 
 
 
 
 
 
 
 
 
mRNA-1010 
 
 
 
 
 
 
 
 
Abbreviations: HA = hemagglutinin; mRNA = messenger ribonucleic acid; NA = not applicable; NTD = N-terminal domain; RBD = receptor-binding domain; 
SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2 
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Table 4: 
mRNA Vaccines in mRNA-1083-P101(Part 2)  
Vaccine 
mRNA Encoding Influenza HA 
mRNA Encoding SARS-CoV-2 Spike 
H1N1 
H3N2 
B/ 
Yamagata 
B/ 
Victoria 
Omicron XBB.1.5 
 RBD-NTD 
Omicron XBB.1.5 
full length 
mRNA-1083 (
) 
 
 
 
 
 
 
mRNA-1083 (
) 
 
 
 
 
 
 
mRNA-1010  
 
 
 
 
 
 
mRNA-1283.815 
 
 
 
 
 
 
mRNA-1273.815 
 
 
 
 
 
 
Abbreviations: HA = hemagglutinin; mRNA = messenger ribonucleic acid; NA = not applicable; NTD = N-terminal domain; RBD = receptor-binding domain; 
SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2 
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mRNA-1083 
Part 1: mRNA-1083.1, mRNA-1083.2, and mRNA-1083.3) 
mRNA-1083 is an LNP-encapsulated, mRNA-based, prophylactic, multi-component vaccine 
encoding antigens from influenza viruses and SARS-CoV-2. mRNA-1083 contains 5 to 6 
mRNAs: 4 sequences that encode membrane-bound hemagglutinin (HA) of the 4 different 
influenza strains recommended by the 
 and 1 to 2 sequences 
that encode the NTD and RBD of the SARS-CoV-2 spike glycoprotein of the recommended 
seasonal variant(s) (Table 3 and Table 4). The NTD and RBD sequences are linked together with 
a short flexible linker and a transmembrane domain anchors the protein to the cell membrane. 
The proteins encoded by mRNA-1083 are also encoded by mRNA-1010 (influenza) and mRNA-
1283 (SARS-CoV-2 bivalent), 
 Four mRNA-1083 vaccine 
compositions will be evaluated in this mRNA-1083-P101 study (Table 3); they contain the same 
5-6 mRNAs 
 
 
Part 1: Contains 6 mRNA sequences that encode for the 4 different influenza strains 
recommended by the WHO 
 and the 2 sequences that encode the NTD 
and RBD of the SARS-CoV-2 spike glycoprotein of the original (Wuhan-Hu 1) and BA.4/BA.5 
variants 
. 
• mRNA-1083.1: 
 
. 
• mRNA-1083.2: 
 
. 
• mRNA-1083.3: 
 
. 
Part 2: mRNA-1083 (
) and mRNA-1083 (
) 
Contains 5 mRNA sequences that encode for the 4 different influenza strains recommended by 
the WHO 
 and the sequence that encodes the NTD and RBD of the 
SARS-CoV-2 spike glycoprotein of the fall/winter 2023-2024 variant XBB.1.5. 
• mRNA-1083
 
. 
• mRNA-1083
 
. 
The Sponsor enrolled Part 1 of this study between Apr to May 2023 with a total of 630 
participants dosed with mRNA-1083 drug products (277 in Cohort A and 353 in Cohort B). The 
IST has reviewed safety data and has not identified significant safety concerns. 
The Phase 3 study completed enrollment between Oct and Nov 2023 to evaluate the safety and 
immunogenicity of mRNA-1083 (
 µg, with 
) 
vs. licensed comparators (
 randomization) (NCT06097273). Approximately 8000 participants 
enrolled in this study and of those, approximately 4000 were dosed with mRNA-1083 drug 
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products (approximately 2000 in the ≥65-year-old age group and 2000 in the 50 to <65-year-old 
age group). No significant safety concerns have been identified to date. 
mRNA-1010 (mRNA-1010  and mRNA-1010) 
mRNA-1010 is an LNP-encapsulated, mRNA-based, prophylactic injection containing 4 mRNAs 
that encode membrane-bound HA of the 4 different influenza strains recommended by the WHO 
. 
Two mRNA-1010 vaccines will be evaluated in this mRNA-1083-P101 study (Table 3 and 
Table 4): 
• mRNA-1010  – Contains the same influenza mRNAs contained in mRNA-1083, 
. 
• mRNA-1010 – Encodes the same influenza HA proteins as mRNA-1083,
 
 
The Sponsor has completed a Phase 1/2 clinical trial of mRNA-1010 (NCT04956575) at dose 
levels up to 
 µg and is now conducting three Phase 3 studies at a 
-µg dose level: two safety 
and immunogenicity clinical trials (mRNA-1010-P301, NCT05415462 and mRNA-1010-P303, 
NCT 05415462) and one safety and efficacy clinical trial (mRNA-1010-P302, NCT05566639). 
More than 15,000 adults have received mRNA-1010 (
 µg) in clinical trials. No significant 
safety concerns have been identified to date. 
mRNA-1283 (mRNA-1283.222, mRNA-1283.815) 
mRNA-1283 is an LNP-encapsulated, mRNA-based prophylactic vaccine that encodes the RBD 
and NTD of the SARS-CoV-2 spike glycoprotein. The NTD and RBD sequences are linked 
together with a short flexible linker and a transmembrane domain anchors the protein to the cell 
membrane. 
Two mRNA-1283 vaccines will be evaluated in this clinical study (Table 3 and Table 4). 
• mRNA-1283.222 - contains 2 mRNAs that encode NTD-RBD of the spike proteins of 
the original (Wuhan-Hu-1) and BA.4/BA.5 variants of SARS-CoV-2 
 
. 
• mRNA-1283.815- encodes the linked NTD-RBD subdomains of the SARS-CoV-2 
spike glycoprotein of the fall/winter 2023-2024 recommended variant XBB.1.5. 
The Sponsor has evaluated mRNA-1283 as a 2-dose primary series in a Phase 1 clinical trial at 
dose levels up to 
 µg (mRNA-1283-P101; NCT04813796) and as a 1-dose booster in a Phase 
2a clinical trial at dose levels up to 
 µg (mRNA-1283-P201; NCT05137236). The mRNA-
1283-P201 clinical trial also evaluated mRNA-1283.211, a bivalent mRNA-1283 vaccine that 
encodes the NTD-RBD of the spike proteins from the original (Wuhan-Hu-1) and B.1.351 
SARS-CoV-2 strains at 
, as a 1-dose booster at dose levels up to 
 µg. 
The Sponsor is currently evaluating mRNA-1283.222 
 µg and mRNA-1283.815 
 µg in a 
Phase 3 study (NCT05815498). More than 6000 adults have received mRNA-1283 in clinical 
trials. No significant safety concerns have been identified to date. 
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mRNA-1273 (mRNA-1273.222, mRNA-1273.815) 
mRNA-1273 is an LNP-encapsulated, mRNA-based prophylactic injection that encodes the 
full-length SARS-CoV-2 prefusion-stabilized spike glycoprotein. 
In Aug 2021, the Sponsor filed a Biologics License Application (BLA) with the United States 
(US) Food and Drug Administration (FDA) for the full licensure of the mRNA-1273 vaccine for 
active immunization to prevent COVID-19 in individuals 18 years of age and older. In January 
2022, the US FDA approved the BLA for SPIKEVAX™ (mRNA-1273) to prevent COVID-19 in 
individuals 18 years of age and older. In November 2021, the US FDA granted Emergency Use 
Authorization (EUA) for an mRNA-1273 booster dose (
 µg) to be given at least 5 months after 
the primary series with mRNA-1273 in adults aged 18 years and older. In March 2022, the FDA 
authorized for EUA of a second booster dose of mRNA-1273 in individuals 50 years and older at 
least 4 months after receipt of a first booster dose. In June 2022, mRNA-1273 was granted EUA 
for the prevention of COVID-19 in children down to 6 months of age in the US and later 
universally recommended the booster for all ages. In August 2022, mRNA-1273.222 bivalent 
(Original + Omicron BA.4/BA.5) booster vaccine was authorized in individuals 18 years and 
older, followed in October 2022 for individuals 6 to 17 years of age. In September 2023, mRNA-
1273.815 (Omicron variant XBB.1.5) was approved in individuals 12 years of age and older and 
authorized in individuals 6 months through 11 years of age. 
Fluarix and Fluzone HD, licensed influenza vaccines 
Fluarix and Fluzone HD are both seasonal, egg-based, quadrivalent vaccines that are licensed for 
the prevention of infection with influenza A and B viruses. Each vaccine contains HAs from the 
4 influenza strains recommended by the WHO. 
Fluarix is a standard-dose vaccine (60 µg of HA) that is approved for children and adults ages 
6 months and above. 
Fluzone HD is a high dose vaccine, containing 4 times the amount of antigen (240 µg of HA) 
than the standard-dose vaccine. In the US, Fluzone HD is approved for adults ≥65 years of age 
and is preferentially recommended for use in that age group. 
2.1. 
Benefit/Risk Assessment  
More detailed information about the known and expected benefits and risks and reasonably 
expected AEs of mRNA-1083 may be found in the Investigator’s Brochure (IB). 
2.1.1. 
Risk Assessment  
As with all injectable vaccines, immediate systemic allergic reactions to vaccination, ranging 
from mild allergic reactions (eg, urticaria) to systemic allergic reactions (eg, anaphylaxis) can 
occur. These reactions are very rare and are estimated to occur once per 450,000 vaccinations for 
vaccines that do not contain allergens such as gelatin or egg protein (Zent et al 2022). Since the 
authorization of the mRNA-1273 vaccine for coronavirus disease 2019 (COVID-19), the US 
CDC estimate of the rate of anaphylaxis based on reporting in the Vaccine Adverse Event 
Reporting System is approximately 2.5 cases/million doses administered (Shimabukuro et al 
2021). As a precautionary measure, all participants will remain under observation at the clinic for 
at least 60 minutes after study intervention administration. 
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Vasovagal syncope (fainting) can occur before or after any vaccination, is usually triggered by 
the pain or anxiety caused by the injection and is not related to the substance injected. Therefore, 
it is important that standard precautions and procedures be followed to avoid injury from 
fainting. 
As with other IM injections, study interventions should be given with caution in individuals 
receiving anticoagulant therapy or those with thrombocytopenia or any coagulation disorder 
(such as hemophilia) because bleeding or bruising may occur following an IM administration in 
these individuals. 
Local adverse reactions (ARs) are expected after intramuscular study intervention 
administration. These are typically mild, transient, and self-limited and may include pain, 
erythema (redness), swelling/induration (hardness) at the injection site and/or ipsilateral 
underarm swelling/tenderness. Systemic ARs may also occur after study intervention 
administration, the majority of which are of mild to moderate in severity. Systemic ARs reported 
with other mRNA vaccines may include fatigue, headache, myalgia, fever, chills, arthralgia, 
vomiting, and/or nausea. 
Laboratory abnormalities (including increases in liver function tests and serum lipase levels) 
following study intervention administration have been observed in early phase clinical studies 
with similar mRNA-based study interventions. These abnormalities were without clinical 
symptoms or signs and returned toward Baseline values over time. The clinical significance of 
these observations is unknown. 
In the postauthorization setting, there have been very rare (<1 in 10,000 recipients) reports of 
myocarditis and pericarditis occurring after vaccination with COVID-19 mRNA vaccines. The 
majority of the cases have been reported in adolescents and young males, within 7 to 14 days 
primarily after the second dose of the vaccine but also after subsequent doses of the vaccine. 
These are typically mild cases and individuals tend to recover within a short time following 
conservative treatment. Healthcare professionals (HPCs) and study participants should be alert to 
the signs and symptoms of myocarditis and pericarditis (Gargano et al 2021). As mentioned 
above, the risk of myocarditis and pericarditis is largely confined to vaccine recipients younger 
than 50 years of age. Therefore, a Baseline ECG and blood will be collected and banked for 
potential future cardiac biomarker assessment in ≥18 to <51 before vaccination to provide a 
comparison should any suspected or confirmed case of myocarditis or pericarditis occur. 
A completed interim analysis of Part 1 of this study showed that all three mRNA-1083 
compositions and doses in mRNA-1083-P101 were generally well tolerated. The majority of 
solicited ARs were Grade 1 or Grade 2 in severity, and most had an onset within 1 to 2 days after 
vaccination. In the mRNA-1083 study arms, participants 18 to <50 years old reported a higher 
frequency of solicited ARs than those in either the 50 to <65 or 65 to <80-year age groups. 
Overall, mRNA-1083 was observed to have an acceptable safety profile with no safety concerns 
identified. 
In a completed Phase 3 study of the mRNA-1273 injection for COVID-19 in 30,420 healthy 
adults, the most frequently reported ARs after any dose of study intervention were pain at the 
injection site, fatigue, headache, myalgia, arthralgia, and chills. The majority of local and 
systemic ARs had a median duration of 1 to 3 days. Adverse reactions from clinical studies with 

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mRNA-1273 occurring in ≥1% of recipients include injection site rash, injection site urticaria, 
rash, and delayed injection site reactions. 
 
 
The Sponsor has completed a Phase 1/2 clinical trial of mRNA-1010 (NCT04956575) at dose 
levels up to 
 µg and is now conducting three Phase 3 studies at a 
-µg dose level: mRNA-
two safety and immunogenicity clinical trials (mRNA-1010-P301, NCT05415462 and mRNA-
1010-P303, NCT 05415462) and one safety and efficacy clinical trial (mRNA-1010-P302, 
NCT05566639). More than 15,000 adults have received mRNA-1010 (
 µg) in clinical trials. 
No significant safety concerns have been identified to date. Based on the final analysis of the 
Phase 1/2 trial, the most common solicited local AR in the mRNA-1010 groups was injection site 
pain and the most common solicited systemic ARs in the 
 µg mRNA-1010 groups were 
fatigue, myalgia, and headache. 
Further details are provided in the current IB. 
2.1.2. 
Benefit Assessment  
The following benefits may accrue to participants: 
• Participants will have a Baseline (Day 1) evaluation for respiratory pathogens, 
including influenza virus and SARS-CoV-2. For Part 1 that is conducted during the 
influenza season, there is ongoing access to evaluation for ILI and/or COVID-19 
throughout the clinical trial. 
• The clinical trial will contribute to the development of a potentially efficacious 
vaccine against seasonal influenza virus and SARS-CoV-2 together as a single 
injection. 
• For participants who receive licensed vaccines (mRNA-1273, Fluzone HD, Fluarix) 
may have protection against influenza and/or SARS-CoV-2 and its variants. 
2.1.3. 
Overall Benefit/Risk Conclusion  
The clinical study aggregate safety data for mRNA-1010, mRNA-1273, and mRNA-1283 
injections demonstrate a similar, consistent and acceptable safety profile supportive of the 
clinical development of the Sponsor mRNA vaccine platform. 
Data from the mRNA-1010-P101 clinical trial, doses tested ranged from 
 µg of 
mRNA-1010) showed no significant safety concerns regarding mRNA-1010. The 
mRNA-1010-P301 (Phase 3, dose tested 
 µg) clinical trial has also been completed. 
Additionally, there are two more Phase 3 studies evaluating mRNA-1010 
 µg 
(mRNA-1010-P302 [NCT05566639], and mRNA-1010-P303 [NCT05827978]) currently 
ongoing. Over 15,000 participants have received mRNA-1010 at 
 mcg in clinical studies. No 
significant safety concerns have been identified. 
Safety from the completed interim analyses of mRNA-1283 injection for COVID-19 in adults 18 
years and older in mRNA-1283-P101 (dose levels up to 
 µg) and in mRNA-1283-201 (dose 
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levels up to 
 µg) revealed no significant safety concerns. The safety and reactogenicity profiles 
of mRNA-1283 (
 μg) and mRNA-1283.11 (
 μg) were overall similar to 
mRNA-1273 (
 μg). The Sponsor is currently evaluating mRNA-1283.222 
 µg and mRNA-
1283.815 
 µg in a Phase 3 study (NCT05815498). More than 6000 adults have received 
mRNA-1283 in clinical trials. No significant safety concerns have been identified to date. 
Safety and efficacy have been established for mRNA-1273. In the post-authorization period, 
there have been very rare reports of anaphylaxis following mRNA-1273 administration. In 
addition, there have been very rare reports of myocarditis and pericarditis occurring after 
vaccination with COVID-19 mRNA vaccines. 
The combined administration of mRNA-1010 and mRNA-1283 as mRNA-1083 may or may not 
offer protection against seasonal influenza and/or COVID-19, respectively. 
Considering the nonclinical data for the combined administration of mRNA-1010 and 
mRNA-1283 vaccines and the clinical safety and immunogenicity data for mRNA-1010, 
mRNA-1283, mRNA-1273.222, and other mRNA vaccines manufactured to date by the Sponsor 
that contain the proprietary SM-102 lipid formulation, the Sponsor considers the potential 
benefits of participation to exceed the risks. 
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3. 
OBJECTIVES AND ENDPOINTS  
3.1. 
Part 1  
The objectives and endpoints for the Part 1 (Phase 1/2) of the study are presented in the table 
below: 
Objectives 
Endpoints 
Primary 
To evaluate the safety and reactogenicity of study 
intervention administration across study treatment 
arms 
• 
Solicited local and systemic ARs through 
7 days after injection 
• 
Unsolicited AEs through 28 days after 
injection 
• 
Unsolicited severe AEs through 28 days after 
injection 
• 
Unsolicited MAAEs from Day 1 to 
Day 181/EoS 
• 
Unsolicited AESIs from Day 1 to 
Day 181/EoS 
• 
SAEs from Day 1 to Day 181/EoS 
• 
Unsolicited AEs leading to discontinuation 
from Day 1 to Day 181/EoS 
Secondary 
To evaluate the humoral immune responses to 
vaccine-matched strains for influenza and 
SARS-CoV-2 across study treatment arms at 
Day 29 
• 
GMT and GMFR at Day 29 compared with 
Day 1 by HAI assay for influenza and by 
PsVNA for SARS-CoV-2 
• 
Influenza: Percentage of participants with 
seroconversion, defined as a Day 29 titer 
 if Baseline is 
 or a 4-fold or 
greater rise if Baseline is 
 in anti-HA 
antibodies measured by HAI assay 
• 
SARS-CoV-2: Percentage of participants 
with seroresponse, defined as a Day 29 titer 
≥4-fold if Baseline is ≥LLOQ or ≥4 × LLOQ 
if Baseline titer is <LLOQ in nAb titers 
measured by PsVNA 
To evaluate the humoral immune responses to 
vaccine-matched strains for influenza and 
SARS-CoV-2 across study treatment arms at all 
evaluable humoral immunogenicity time points 
• 
GMT and GMFR at all evaluable timepoints 
compared with Day 1 by HAI for influenza 
and PsVNA for SARS-CoV-2 
• 
Influenza: Percentage of participants with 
seroconversion, as defined above 
• 
SARS-CoV-2: Percentage of participants 
with seroresponse, as defined above 
Exploratory (may be performed) 
To evaluate the humoral immune responses to 
vaccine-mismatched strains for influenza and 
SARS-CoV-2 across study treatment arms 
• 
GMT and GMFR at all evaluable timepoints 
compared with Day 1 by HAI for influenza 
and PsVNA for SARS-CoV-2 
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Objectives 
Endpoints 
• 
Influenza: Percentage of participants with 
seroconversion, as defined above 
• 
SARS-CoV-2: Percentage of participants 
with seroresponse, as defined above 
To evaluate the humoral immune responses 
against vaccine-matched and vaccine-mismatched 
strains for influenza and SARS-CoV-2 across 
study treatment arms 
• 
GMT and GMFR at all evaluable timepoints 
compared with Day 1 by alternative methods, 
including, but not limited to: 
microneutralization assay for influenza or 
ligand-binding assay for SARS-CoV-2 
To evaluate the cellular immune responses against 
influenza and SARS-CoV-2 in a subset of 
participants 
• 
Frequency, magnitude, and phenotype of 
virus-specific T-cell and B-cell responses 
measured by flow cytometry or other 
methods 
• 
Perform targeted repertoire analysis of 
B-cells and T-cells after injection 
To further characterize the immune response to 
influenza and SARS-CoV-2 across study 
treatment arms 
• 
Frequency, specificities, or other endpoints to 
be determined for the further characterization 
of immune responses 
To assess the occurrence of clinical influenza and 
COVID-19 in study participants and characterize 
their immune response to infection and viral 
isolates 
• 
Frequency of RT-PCR-confirmed clinical 
influenza and COVID-19 
• 
Assessment of immune responses to infection 
and viral isolates 
Abbreviations: AE = adverse event; AR = adverse reaction;; COVID-19 = coronavirus disease 2019; EoS = end of 
study; GMFR = geometric mean fold rise; GMT = geometric mean titer; HA = hemagglutination; 
HAI = hemagglutination inhibition; LLOQ = lower limit of quantification; MAAE = medically attended adverse 
event; nAb = neutralizing antibody; PsVNA = pseudovirus neutralization assay; RT-PCR = reverse transcription 
polymerase chain reaction; SAR-CoV-2 = severe acute respiratory syndrome coronavirus 2. 
3.2. 
Part 2  
The objectives and endpoints for the Part 2 (Phase 2) of the study are presented below: 
Objectives 
Endpoints 
Primary 
To evaluate the safety and reactogenicity of study 
intervention administration across study treatment 
arms 
• 
Solicited local and systemic ARs through 7 days 
after injection 
• 
Unsolicited AEs through 28 days after injection 
• 
Unsolicited Severe AEs through 28 days after 
injection 
• 
Unsolicited MAAEs from Day 1 to 
Day 181/EoS 
• 
Unsolicited AESIs from Day 1 to Day 181/EoS 
• 
SAEs from Day 1 to Day 181/EoS 
• 
Unsolicited AEs leading to discontinuation from 
Day 1 to Day 181/EoS 

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Objectives 
Endpoints 
To evaluate the humoral immune responses to 
vaccine-matched strains for influenza and 
SARS-CoV-2 across study treatment arms at 
Day 29 
• GMT and GMFR at Day 29 compared to 
Day 1 by HAI assay for influenza and by 
PsVNA for SARS-CoV-2 
• Influenza: Percentage of participants with 
seroconversion, defined as a Day 29 titer 
 if Baseline is 
 or a 4-fold or 
greater rise if Baseline is 
 in anti-HA 
antibodies measured by HAI assay 
• SARS-CoV-2: Percentage of participants 
with seroresponse, defined as a Day 29 titer 
≥4-fold if Baseline is ≥LLOQ or ≥4 × 
LLOQ if Baseline titer is <LLOQ in nAb 
titers measured by PsVNA 
Secondary 
To evaluate the humoral immune responses to 
vaccine-matched strains for influenza and 
SARS-CoV-2 across study treatment arms at all 
evaluable humoral immunogenicity time points 
• 
GMT and GMFR at all evaluable time points 
compared to Day 1 by HAI for influenza and 
PsVNA for SARS-CoV-2 
• 
Influenza: Percentage of participants with 
seroconversion, as defined above 
• 
SARS-CoV-2: Percentage of participants with 
seroresponse, as defined above 
Exploratory (may be performed) 
To evaluate the humoral immune responses to 
vaccine-mismatched strains for influenza and 
SARS-CoV-2 across study treatment arms 
• 
GMT and GMFR at all evaluable time points 
compared to Day 1 by HAI for influenza and 
PsVNA for SARS-CoV-2 
• 
Influenza: Percentage of participants with 
seroconversion, as defined above 
• 
SARS-CoV-2: Percentage of participants with 
seroresponse, as defined above 
To evaluate the humoral immune responses 
against vaccine-matched and vaccine-mismatched 
strains for influenza and SARS-CoV-2 across 
study treatment arms 
• 
GMT and GMFR at all evaluable time points 
compared to Day 1 by alternative methods, 
including, but not limited to: microneutralization 
assay for influenza or ligand-binding assay for 
SARS-CoV-2 
To further characterize the immune response to 
influenza and SARS-CoV-2 across study 
treatment arms 
• 
Frequency, specificities, or other endpoints to be 
determined for the further characterization of 
immune responses 
Abbreviations: AE = adverse event; AR = adverse reaction;; COVID-19 = coronavirus disease 2019; EoS = end of 
study; GMFR = geometric mean fold rise; GMT = geometric mean titer; HA = hemagglutination; 
HAI = hemagglutination inhibition; LLOQ = lower limit of quantification; MAAE = medically attended adverse 
event; nAb = neutralizing antibody; PsVNA = pseudovirus neutralization assay; RT-PCR = reverse transcription 
polymerase chain reaction; SAR-CoV-2 = severe acute respiratory syndrome coronavirus 2. 
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4. 
STUDY DESIGN  
4.1. 
Overall Design  
The study is divided into 2 parts: 
Part 1 of the study will be a Phase 1/2 randomized, stratified, observer-blind, active-control study 
to evaluate the safety, reactogenicity, and immunogenicity of mRNA-1083 compositions and 
dose levels compared with active-control vaccines mRNA-1010, mRNA-1283.222, 
mRNA-1273.222, and licensed active-control vaccines, Fluarix and Fluzone® HD (Cohort A 
only) in healthy adults ≥18 to <80 years of age (Cohort A is in adults ≥65 to <80 years of age 
and Cohort B is in adults ≥18 to <65 years of age). 
Approximately, 1224 participants will be enrolled into 1 of 2 age cohorts: Cohort A for adults 
≥65 to <80 years of age or Cohort B for adults ≥18 to <65 year of age. In Cohort A, 
approximately 600 participants will be randomized (in equal allocation ratio) into the 
investigational treatment arms, stratified by influenza vaccine status in the most recent influenza 
season (received or not received since September 2022). In Cohort B, approximately 624 
participants will be randomized (in equal allocation ratio) into the investigational treatment arms, 
stratified by 2 age groups: ≥18 to <50 years and ≥50 to <65 years of age and by influenza 
vaccine status in the most recent influenza season (received or not received since September 
2022). Approximately 50% of the participants in Cohort B will be ≥50 to <65 years of age. 
Part 2 of the study will be a Phase 2 randomized, stratified, observer-blind, active-control study 
to evaluate the safety, reactogenicity, and immunogenicity of mRNA-1083 compositions and 
dose levels compared with active-control vaccines mRNA-1010, mRNA-1283.815, 
mRNA-1273.815, and licensed active-control vaccine, Fluarix in young healthy adults ≥18 to 
<50 years of age. 
Approximately, 520 participants between ≥18 to <50 years of age will be randomized (in equal 
allocation ratio) into the investigational treatment arms, stratified by influenza vaccine status in 
the most recent influenza season (received or not received since Sept 2023). 
The study will be performed in 2 parts, and results for each part of the study will be provided as 
a separate clinical study report. 
4.2. 
Scientific Rationale for Study Design  
The Sponsor is developing mRNA-1083, a lipid-encapsulated mRNA-based prophylactic 
combination vaccine encoding influenza and SARS-CoV-2 antigens. mRNA-1083 contains 5 to 
6 mRNAs: 4 sequences encoding surface glycoprotein hemagglutinin (HA) of seasonal influenza 
viruses and 1 to 2 sequences encoding linked NTD and RBD of SARS-CoV-2 spike proteins. 
mRNA-1083 encodes the respective antigens also encoded by mRNA-1010 (seasonal influenza) 
and mRNA-1283 (SARS-CoV-2 booster). 
The administration of the mRNA-1083 vaccine has the potential to efficiently reduce the overall 
burden of acute viral respiratory diseases by providing simultaneous protection against influenza 
and SARS-CoV-2 viruses in a convenient dosing regimen. mRNA-1083 offers greater 
convenience and has the potential to lead to increased compliance with vaccine 
recommendations, an approach which has been frequently used for pediatric vaccines 

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(Kurosky et al 2017). Furthermore, this combined regimen could provide a public health benefit 
through synergistically increasing coverage rates against influenza and SARS-CoV-2 viruses. 
This clinical trial aims to generate safety, reactogenicity, and immunogenicity data of the 
mRNA-1083 multicomponent influenza and SARS-CoV-2 vaccine in adults aged ≥18 to 
<80 years. 
The study is divided into 2 parts: Part 1 and Part 2. Part 1 (Phase 1/2) includes adults who are 18 
to <80 years and Part 2 (Phase 2 Extension) includes adults who are 18 to <50 years. 
4.3. 
Justification for Dose  
The selected dose levels in this clinical trial are based on the clinical experience with the 
component vaccines mRNA-1010 and mRNA-1283, which were evaluated for safety up to 
 µg and 
 µg, respectively. In clinical trials, at least 15,000 adults have been dosed with 
mRNA-1010 and approximately 6000 participants have been dosed with mRNA-1283. 
All of the proposed dosages of mRNA-1083 are lower than maximum dosages of the 
mRNA-1010 and mRNA-1283 components studied previously in clinical studies. 
 
4.4. 
End of Study Definition  
For each of the study (Part 1 and Part 2), a participant is considered to have completed the 
clinical trial once they have completed all periods of the clinical trial including the last scheduled 
procedure as shown in the Schedule of Assessments (SoA), Section 1.3. 
The EoS is defined as completion of the last visit of the last participant in the clinical trial or last 
scheduled procedure as shown in the SoA for the last participant in each part of the clinical trial 
globally. 
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5. 
STUDY POPULATION  
This clinical trial will enroll adult participants ≥18 to <80 years of age. Prospective approval of 
protocol deviations to recruitment and enrollment criteria, also known as protocol waivers or 
exemptions, is not permitted. 
5.1. 
Part 1 (Phase 1/2)  
5.1.1. 
Inclusion Criteria  
Participants are eligible to be included in the clinical trial only if all the following criteria apply: 
Age 
1. Adults ≥18 to <80 years of age at the time of consent. 
Weight 
2. Body mass index (BMI) of 18 kg/m2 to 35 kg/m2 (inclusive) at the Screening Visit. 
Type of Participant and Disease Characteristics 
3. Investigator assessment that participant understands and is willing and physically able to 
comply with protocol-mandated follow-up, including all procedures. 
4. Healthy as determined by medical evaluation, including medical history, physical 
examination, and laboratory tests. 
Sex and Contraceptive/Barrier Requirements 
5. Participants of nonchildbearing potential may be enrolled in the study. Nonchildbearing 
potential is defined as postmenopausal or permanently sterilized as described in 
Section 10.6. A FSH level may be measured at the discretion of the Investigator to 
confirm postmenopausal status. 
6. Participants of childbearing potential may be enrolled in the study if they fulfill all of the 
following criteria: 
• Have a negative pregnancy test at the Screening Visit and on the day of study 
intervention administration. 
• Have practiced adequate contraception, as described in Section 10.6, or have 
abstained from all activities that could result in pregnancy for at least 28 days prior to 
Day 1. 
• Has agreed to continue adequate contraception, as described in Section 10.6, or 
abstain from all activities that could result in pregnancy through 90 days following 
study intervention administration. 
7. Is not currently breast/chestfeeding. 
Informed Consent 
8. Capable of giving signed informed consent as described in Section 10.1.4, which includes 
compliance with the requirements and restrictions listed in the informed consent form 
(ICF) and in this protocol. 

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Other Inclusion Criteria 
9. Fully vaccinated for COVID-19 primary series according to the locally authorized or 
approved regimen, and their last COVID-19 vaccine (primary series or booster) was 
≥120 days prior to Day 1. 
5.1.2. 
Exclusion Criteria  
Participants are excluded from the clinical trial if any of the following criteria apply: 
Medical Conditions 
1. Acutely ill or febrile (temperature ≥38.0℃ [100.4°F]) 72 hours prior to or at the 
Screening Visit or Day 1. Participants meeting this criterion may be rescheduled within 
the 28-day Screening window and will retain their initially assigned participant number. 
2. Clinical screening laboratory values (white blood cell count, hemoglobin, hematocrit, 
platelets, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, 
alkaline phosphatase, and total bilirubin) >Grade 1 or platelets ≥Grade 1 (DHHS 2007). 
3. Significant, progressive, unstable, or uncontrolled clinical condition, including any 
condition that may affect participant safety, assessment of safety endpoints, assessment 
of immune response, or adherence to study procedures per Investigator judgment. 
4. Participants who have undergone surgical procedures within 28 days prior to Day 1 or are 
scheduled to undergo a surgical procedure within 28 days after study intervention 
administration are also excluded. However, minor surgical procedures under local 
anesthesia (eg, excision of skin lesion) or diagnostic procedures (eg, colonoscopy) are 
allowed. 
5. Reported history of congenital or acquired immunodeficiency (eg, HIV), 
immunocompromizing/immunosuppressive condition, asplenia, or recurrent severe 
infections. The following conditions are permitted at the discretion of the Investigator: 
Certain immune-mediated conditions that are stable and well-controlled (eg, Hashimoto 
thyroiditis) as well as those that do not require systemic immunosuppressants per Exclusion 
Criterion 15 (eg, asthma, psoriasis, or vitiligo), are permitted at the discretion of the Investigator. 
6. Dermatologic conditions that could affect local solicited AR assessments (eg, tattoos, 
psoriasis patches affecting skin over the deltoid areas). 
7. Reported history of anaphylaxis or severe hypersensitivity reaction after receipt of any 
mRNA or influenza vaccines or any components of the mRNA or influenza vaccines, 
including egg protein. 
8. Has coagulopathy or bleeding disorder considered a contraindication to IM injection or 
phlebotomy. 
9. Diagnosis of malignancy within previous 5 years (excluding nonmelanoma skin cancer). 
10. Any medical, psychiatric, or occupational condition, including reported history of drug or 
alcohol abuse, that, in the opinion of the Investigator, might pose additional risk due to 
participation in the clinical trial or could interfere with the interpretation of study results. 
11. Has a history of myocarditis, pericarditis, or myopericarditis.  
12. Has a history of Guillain-Barre syndrome. 
13. Participant has known history of SARS-CoV-2 infection within ≤90 days prior to Day 1. 
14. Tested positive for influenza by local health authority-approved testing methods 
≤150 days prior to Day 1. 

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Prior/Concomitant Therapy 
15. Received systemic immunosuppressants for >14 days in total within 180 days prior to 
Screening Visit (for glucocorticoids ≥10 mg/day of prednisone or equivalent) or is 
anticipating the need for systemic immunosuppressive treatment at any time during 
participation in the clinical trial (including intra-articular steroid injections). Inhaled, 
nasal, and topical steroids are allowed. 
16. Received or plans to receive any vaccine authorized or approved by a local health agency 
≤28 days prior to study intervention administration or plans to receive a vaccine 
authorized or approved by a local health agency within 28 days after study intervention 
administration. 
17. Received a seasonal influenza vaccine or any other investigational influenza vaccine 
within 150 days prior to Day 1. 
18. Treated with antiviral therapies for influenza (eg, Tamiflu®) within 150 days prior to the 
Day 1. 
19. Treated with any other non-influenza antiviral therapies (including antivirals for treating 
individuals with HIV or in at-risk individuals as pre-exposure prophylaxis) within 
14 days prior to Day 1 or plans to use antiviral therapies within 28 days of study 
intervention administration. 
20. Has received systemic immunoglobulins or blood products ≤90 days prior to the 
Screening Visit or plans to receive systemic immunoglobulins or blood products during 
the clinical trial. 
Prior/Concurrent Clinical Study Experience 
21. Participated in an interventional clinical study within 28 days prior to the Screening Visit 
or plans to do so while participating in this clinical trial. Participants may continue in 
prior interventional study follow-up activities if it does not involve further investigational 
treatment. Note: Interventions such as counseling, biofeedback, and cognitive therapy are 
not exclusionary. 
Other Exclusion Criteria 
22. Unaware whether they received an influenza vaccine during or since September 2022. 
23. Has had close contact to someone with COVID-19 as defined by the CDC in the past 
10 days prior to Day 1. 
24. Had close contact with someone with laboratory-confirmed influenza infection or with 
someone who has been treated with antiviral therapies for influenza (eg, Tamiflu) within 
the past 5 days prior to Day 1. 
25. Has donated ≥450 mL of blood products within 28 days prior to the Screening Visit or 
plans to donate blood products during the clinical trial. 
26. Working or has worked as study personnel, is an immediate family member or household 
member of study personnel, study site staff, or Sponsor personnel, or resides in a nursing 
home. 
5.2. 
Part 2 (Phase 2 Extension)  
5.2.1. 
Inclusion Criteria  
Participants are eligible to be included in the clinical trial only if all the following criteria apply: 

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Age 
1. Adults ≥18 to <50 years of age at the time of consent. 
Weight 
2. Body mass index (BMI) of 18 kg/m2 to 35 kg/m2 (inclusive) at the Screening Visit. 
Type of Participant and Disease Characteristics 
3. Investigator assessment that participant understands and is willing and physically able to 
comply with protocol-mandated follow-up, including all procedures. 
4. Healthy as determined by medical evaluation, including medical history, and physical 
examination. 
Sex and Contraceptive/Barrier Requirements 
5. Participants of nonchildbearing potential may be enrolled in the study. Nonchildbearing 
potential is defined as postmenopausal or permanently sterilized as described in 
Section 10.6. A FSH level may be measured at the discretion of the Investigator to 
confirm postmenopausal status. 
6. Participants of childbearing potential may be enrolled in the study if they fulfill all of the 
following criteria: 
• Have a negative pregnancy test at the Screening Visit and on the day of study 
intervention administration. 
• Have practiced highly effective contraception, as described in Section 10.6, or have 
abstained from all activities that could result in pregnancy for at least 28 days prior to 
Day 1. 
• Has agreed to continue adequate contraception, as described in Section 10.6, or 
abstain from all activities that could result in pregnancy through 90 days following 
study intervention administration. 
7. Is not currently breast/chestfeeding. 
Informed Consent 
8. Capable of giving signed informed consent as described in Section 10.1.4, which includes 
compliance with the requirements and restrictions listed in the ICF and in this protocol. 
Other Inclusion Criteria 
9. Have received at least 2 doses of locally authorized or approved COVID-19 vaccines and 
last dose was >= 90 days prior to Day 1. 
5.2.2. 
Exclusion Criteria  
Participants are excluded from the clinical trial if any of the following criteria apply: 
Medical Conditions 
1. Participants who enrolled in Part 1 of the mRNA-1083-P101 (Phase 1/2) study. 

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2. Acutely ill or febrile (temperature ≥38.0℃ [100.4°F]) 72 hours prior to or at the 
Screening Visit or Day 1. Participants meeting this criterion may be rescheduled within 
the 28-day Screening window and will retain their initially assigned participant number. 
3. Significant, progressive, unstable, or uncontrolled clinical condition, including any 
condition that may affect participant safety, assessment of safety endpoints, assessment 
of immune response, or adherence to study procedures per Investigator judgment 
(including but not limited to the following examples: IBD, CKD Grade ≥2 or higher), 
CHF). 
4. Participants who have undergone surgical procedures within 28 days prior to Day 1 or are 
scheduled to undergo a surgical procedure within 28 days after study intervention 
administration are also excluded. However, minor surgical procedures under local 
anesthesia (eg, excision of skin lesion) or diagnostic procedures (eg, colonoscopy) are 
allowed. 
5. Reported history of congenital or acquired immunodeficiency (eg, HIV), 
immunocompromizing/immunosuppressive condition, asplenia, or recurrent severe 
infections. The following conditions are permitted at the discretion of the Investigator: 
Certain immune-mediated conditions that are stable and well-controlled (eg, Hashimoto 
thyroiditis) as well as those that do not require systemic immunosuppressants per 
Exclusion Criterion 15 (eg, asthma, psoriasis, or vitiligo), are permitted at the discretion of the 
Investigator. 
6. Dermatologic conditions that could affect local solicited AR assessments (eg, tattoos, 
psoriasis patches affecting skin over the deltoid areas). 
7. Reported history of anaphylaxis or severe hypersensitivity reaction after receipt of any 
mRNA or influenza vaccines or any components of the mRNA or influenza vaccines, 
including egg protein. 
8. Has coagulopathy or bleeding disorder considered a contraindication to IM injection or 
phlebotomy. 
9. Any malignancy within previous 5 years (excluding nonmelanoma skin cancer). 
10. Any medical, psychiatric, or occupational condition, including reported history of drug or 
alcohol abuse, that, in the opinion of the Investigator, might pose additional risk due to 
participation in the clinical trial or could interfere with the interpretation of study results. 
11. Has a history of myocarditis, pericarditis, or myopericarditis with onset within 90 days 
prior to Day 1 or whose values have not returned to Baseline clinical status.  
12. Has a history of Guillain-Barre syndrome. 
13. Participant has known history of SARS-CoV-2 infection within ≤90 days prior to Day 1. 
14. Tested positive for influenza by local health authority-approved testing methods 
≤150 days prior to Day 1. 
Prior/Concomitant Therapy 
15. Received systemic immunosuppressants for >14 days in total within 180 days prior to 
Screening Visit (for glucocorticoids ≥10 mg/day of prednisone or equivalent) or is 
anticipating the need for systemic immunosuppressive treatment at any time during 
participation in the clinical trial (including intra-articular steroid injections). Inhaled, 
nasal, and topical steroids are allowed. 
16. Received or plans to receive any vaccine authorized or approved by a local health agency 
≤28 days prior to study intervention administration or plans to receive a vaccine 

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authorized or approved by a local health agency within 28 days after study intervention 
administration. 
17. Received a seasonal influenza vaccine ≤150 days prior to Day 1. 
18. Received any investigational seasonal influenza vaccine study ≤12 months prior to Day 1 
19. Treated with antiviral therapies for influenza (eg, Tamiflu®) within 150 days prior to the 
Day 1. 
20. Treated with any other non-influenza antiviral therapies (including antivirals for treating 
individuals with HIV or in at-risk individuals as pre-exposure prophylaxis) within 
14 days prior to Day 1 or plans to use antiviral therapies within 28 days of study 
intervention administration. 
21. Has received systemic immunoglobulins or blood products ≤90 days prior to the 
Screening Visit or plans to receive systemic immunoglobulins or blood products during 
the clinical trial. 
Prior/Concurrent Clinical Study Experience 
22. Participated in an interventional clinical study within 28 days prior to the Screening Visit 
or plans to do so while participating in this clinical trial. Participants may continue in 
prior interventional study follow-up activities if it does not involve further investigational 
treatment. Note: Interventions such as counseling, biofeedback, and cognitive therapy are 
not exclusionary. 
Other Exclusion Criteria 
23. Unaware whether they received an influenza vaccine during or since September 2023. 
24. Has had close contact to someone with COVID-19 as defined by the CDC in the past 
10 days prior to Day 1. 
25. Had close contact with someone with laboratory-confirmed influenza infection or with 
someone who has been treated with antiviral therapies for influenza (eg, Tamiflu) within 
the past 5 days prior to Day 1. 
26. Has donated ≥450 mL of blood products within 28 days prior to the Screening Visit or 
plans to donate blood products during the clinical trial. 
Working or has worked as study personnel, is an immediate family member or household 
member of study personnel, study site staff, or Sponsor personnel, or resides in a nursing home. 
5.3. 
Lifestyle Restrictions  
Participants must not eat or drink anything hot or cold within 10 minutes before oral temperature 
is taken. 
Participants in the clinical trial should defer vaccination with licensed seasonal influenza vaccine 
or an authorized/licensed COVID-19 vaccine until after completion of their Day 29 visit, and 
ideally until Day 181. If such vaccines are available, participants should discuss with the 
Investigators prior to receiving these nonstudy vaccines. 
5.4. 
Screen Failures  
Screen failures are defined as participants who consent to participate in the clinical study but are 
not subsequently assigned to treatment. A minimum set of screen failure information is required 
to ensure transparent reporting of screen failures to meet the Consolidated Standards of 

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Reporting Trials publishing requirements and to respond to queries from regulatory authorities. 
Minimum information includes date of informed consent, demography, reason(s) for screen 
failure, eligibility criteria. 
Individuals who do not meet the criteria for participation in this clinical trial (screen failure) may 
be rescreened one time. 

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6. 
STUDY INTERVENTION(S) AND CONCOMITANT THERAPY  
Study interventions are all prespecified, investigational, and non-investigational products, 
medical devices and other interventions (eg, surgical and behavioral) intended to be administered 
to the study participants during the clinical trial conduct. 
6.1. 
Study Intervention(s) Administered  
The Sponsor is using its mRNA-based platform to develop a custom-manufactured LNP-
encapsulated, mRNA-based vaccines against diseases caused by influenza virus types A and B 
and SARS-CoV-2. The mRNA vaccines to be used in this clinical study are shown in Table 3 
(Part 1) and Table 4 (Part 2). The mRNAs comprising each vaccine are formulated in a mixture 
of 4 lipids: SM-102, cholesterol, DSPC, and PEG200-DMG. All injections are administered 
intramuscularly (IM). 
6.1.1. 
Part 1 (Phase 1/2)  
In Part 1 of the study, all participants will receive a single IM injection of study intervention 
(Table 5) administered in a deltoid muscle on Day 1. 
The components of the mRNA vaccines to be used in Part 1 of are shown in Table 3. 
The term investigational product (IP) in Part 1 of the study refers to the mRNA-1083 (mRNA-
1083.1, mRNA-1083.2, mRNA-1083.3). Non-IP experimental comparators administered in this 
clinical trial are mRNA-1010 , mRNA-1010, mRNA-1283.222, and mRNA-1273.222 vaccines. 
Fluarix and Fluzone HD are licensed vaccine comparators. 
Table 5: 
Study Arm(s) and Interventions (Part 1 – Phase 1/2)  
Cohort A 
Arms: 
(≥65 to <80 
years), 
n=50/arm, 600 
total 
Cohort B 
Arms: 
(≥18 to <65 
years), 
n=52/arm, 624 
total 
Intervention 
Total mRNA
Dose (µg)  
Intervention 
Type 
NA 
B1 
mRNA-1083.1 
IP 
A2 
B2 
mRNA-1083.1 
IP 
A3 
B3 
mRNA-1083.1 
IP 
A4 
B4 
mRNA-1083.2 
IP 
A5 
B5 
mRNA-1083.2 
IP 
A6 
B6 
mRNA-1083.2 
IP 
A7 
B7 
mRNA-1083.3 
IP 
A8 
B8 
mRNA-1010  
Non-IP 
experimental 
comparator 
A9 
B9 
mRNA-1283.222 
Non-IP 
experimental 
comparator 
A10 
B10 
mRNA-1273.222 
Non-IP 
experimental 
comparator 
CCI
CCI
CCI
CC
CCI

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Cohort A 
Arms: 
(≥65 to <80 
years), 
n=50/arm, 600 
total 
Cohort B 
Arms: 
(≥18 to <65 
years), 
n=52/arm, 624 
total 
Intervention 
Total mRNA
Dose (µg)  
Intervention 
Type 
A11 
B11 
mRNA-1010 
Non-IP 
experimental 
comparator 
A12 
B12 
Fluarix 
Licensed vaccine 
comparator 
A13 
NA 
Fluzone HD 
Licensed vaccine 
comparator 
Total mRNA dose is rounded to the nearest 
 µg. 
Abbreviations: HD = high dose; IP = investigational product; mRNA = messenger ribonucleic acid; NA = not 
applicable; SARS-Cov-2 = severe acute respiratory syndrome coronavirus 2 
6.1.2. 
Part 2 (Phase 2 - Extension)  
In Part 1 of the study, all participants will receive a single IM injection of study intervention 
(Table 6) administered in a deltoid muscle on Day 1. 
The components of the mRNA vaccines to be used in Part 2 are shown in Table 4. 
The term IP in Part 2 of the study refers to mRNA-1083 (
 and mRNA-1083 
). Non-IP experimental comparators administered in this clinical trial are mRNA-1010 , 
mRNA-1283.815 and mRNA-1273.815 vaccines. Fluarix is the licensed vaccine comparator. 
Table 6: 
Study Arm(s) and Interventions (Part 2 – Phase 2 Extension)  
Part 2 Arm: 
(≥18 to <50 years), 
n=40/arm, 520 total 
Intervention 
Intervention 
Type 
1 
mRNA-1083 
 
IP 
2 
mRNA-1083 
 
IP 
3 
mRNA-1083 
 
IP 
4 
mRNA-1083 
 
IP 
5 
mRNA-1083 
 
IP 
6 
mRNA-1083 
 
IP 
7 
mRNA-1083 
 
IP 
8 
mRNA-1083 
 
IP 
9 
mRNA-1010  
Non-IP experimental comparator 
10 
mRNA-1010  
Non-IP experimental comparator 
11 
mRNA-1283.815 
Non-IP experimental comparator 
12 
mRNA-1273.815 
Licensed vaccine 
comparator 
13 
Fluarix 
Licensed vaccine 
comparator 
CC
CCI
CCI
CCI
CCI
CCI
CCI
CCI
CCI
CCI
CCI
CCI
CCI
CCI
CCI
CCI
CCI
CCI
C

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6.2. 
Preparation, Handling, Storage, and Accountability  
The Investigator or designee must confirm appropriate conditions (eg, temperature) have been 
maintained during transit for all study interventions received, and any discrepancies are reported 
and resolved before use of any study intervention. 
Only participants enrolled in the clinical trial may receive study intervention, and only 
authorized site staff may supply, prepare, or administer study intervention. 
All study interventions must be stored in a secure, environmentally controlled, and monitored 
(manual or automated) area in accordance with the labeled storage conditions with access limited 
to the Investigator and authorized site staff. 
See full prescribing information for detailed information for the preparation, handling, and 
storage of Fluarix (Glaxosmithkline Biologicals) and Fluzone HD (Sanofi Pasteur Inc). 
6.2.1. 
Preparation of Study Injection  
The IP, non-IP, and experimental comparators preparation instructions are detailed in the 
Pharmacy Manual. 
6.2.2. 
Clinical Study Material Packaging and Labeling  
All IPs used in this clinical trial will be prepared, packaged, and labeled in accordance with the 
standard operating procedures of ModernaTX, Inc. or those of its designee, Code of Federal 
Regulations (CFR) Title 21, Good Manufacturing Practice guidelines, International Conference 
on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human 
Use GCP guidelines, guidelines for Quality System Regulations, and applicable regulations. For 
further direction, refer to the Pharmacy Manual. 
6.2.3. 
Clinical Study Material Storage  
The study intervention will have all required labeling per regulations and will be supplied to the 
pharmacy. 
All study interventions used in this study will be prepared, packaged, and labeled in accordance 
with the standard operating procedures of the Sponsor or of its designee, CFR Title 21 GMP 
guidelines, ICH GCP guidelines, guidelines for Quality System Regulations, and applicable 
regulations. For further direction, refer to the Pharmacy Manual. 
6.2.4. 
Clinical Study Material Accountability  
It is the Investigator’s responsibility that the IP accountability study staff maintain accurate 
records in an IP accountability log of receipt of all IP, site IP inventory, IP dispensing, IP 
injections, and return to the Sponsor or alternative disposition of used and unused IP vials. 
A site monitor will review the inventory and accountability log during site visits and at the 
completion of the clinical trial. For further direction, refer to the Pharmacy Manual. 

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6.2.5. 
Clinical Study Material Handling and Disposal  
A site monitor will reconcile the clinical study material during clinical trial conduct and at the 
end of the clinical trial for compliance. Once fully reconciled at the site, the clinical study 
material can be destroyed at the study site or Sponsor-selected third party, as appropriate. 
Study products may be destroyed at the clinic only if permitted by local regulations and 
authorized by the Sponsor. A Certificate of Destruction must be obtained and sent to the Sponsor 
or designee. For further direction, refer to Pharmacy Manual. 
6.3. 
Assignment to Study Intervention  
Randomization will be performed using an interactive response technology (IRT). 
6.4. 
Blinding  
The treatment assignment, including the injection site and the corresponding vaccine 
administered, will be concealed by having the delegated unblinded study personnel prepare the 
study intervention in a secure location that is not accessible or visible to other study staff. An 
opaque sleeve over the syringe used for injection will maintain the blind at the time of injection. 
Only delegated unblinded study site staff will conduct the injection procedure. Once the injection 
is completed, only the blinded study staff will perform further assessments and interact with the 
participants. Access to the randomization code will be strictly controlled at the pharmacy. 
Except in the case of medical necessity, a participant’s vaccine assignment should not be 
unblinded without the approval of the Sponsor. If a participant becomes seriously ill or pregnant 
during the clinical trial, the blind will be broken only if knowledge of the vaccine assignment 
will affect that participant’s clinical management. In the event of a medical emergency requiring 
identification of individual vaccine assignment, the Investigator will make every attempt to 
contact the clinical research organization (CRO)’s medical monitor, preferably via electronic 
protocol inquiry platform, to explain the need for unblinding within 24 hours of opening the 
code. The Investigator will be responsible for documenting the time, date, reason for unblinding, 
and the names of the personnel involved. The Investigator (or designee) will have access to 
unblind participants within IRT. All unblinding instances will be tracked via an audit trail in IRT 
and documented in the clinical study report (CSR). 
If unblinding should occur (by either accidental unblinding or emergency unblinding) before 
completion of the clinical trial, the Investigator must promptly contact the Sponsor and document 
the circumstances on the appropriate forms. 
In addition to the aforementioned situations where the blind may be broken, the data will also be 
unblinded to a statistical team at specified timepoint(s) for analysis as outlined in Section 9.1. 
6.5. 
Study Intervention Compliance  
All study interventions will be administered by qualified and trained study personnel to ensure 
that all doses administered comply with those planned. Study intervention administration will be 
recorded in the electronic case report form (eCRF). Administration data will be reconciled with 
site accountability records to determine compliance. 

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6.6. 
Dose Modification  
No dose modifications will be made to the study interventions as planned. 
6.7. 
Criteria for Temporarily Delaying Study Vaccination  
Body temperature must be measured before study intervention administration. The following 
events constitute criteria for delay of study intervention administration, and if either of these 
events occur at the time scheduled for dosing, the participant may be injected at a later date 
within the time window specified in the SoA (Table 1), or the participant may be discontinued 
from dosing at the discretion of the Investigator (Section 7.2): 
• Acute, moderate, or severe infection with or without fever at the time of dosing 
• Fever, defined as body temperature ≥38.0°C (100.4°F) at the time of dosing 
Participants with a fever ≥38.0°C (100.4°F) 72 hours prior to or at the Screening Visit or Day 1 
may be rescheduled within the 28-day Screening window and will retain their initially assigned 
participant number. If the Investigator determines that the participant’s health on the day of 
dosing temporarily precludes study intervention administration, the visit should be rescheduled 
within the allowed interval for that visit. 
If a participant takes a prohibited drug therapy, study intervention administration could be 
delayed within the visit window based on the joint decision of the Investigator and the CRO’s 
medical monitor (Section 6.10.3). 
6.8. 
Treatment of Overdose  
As study intervention is to be administered by a healthcare professional (HCP), it is unlikely that 
an overdose will occur, as each participant will receive a single injection. However, in the event 
of an overdose, the Investigator should: 
• Contact the Medical Monitor immediately. 
• Closely monitor the participant for any AE/SAE and laboratory abnormalities until 
the last safety follow-up visit. 
• Report any signs or symptoms associated with the overdose as an AE and record 
details in the relevant AE/SAE sections in the electronic data capture (EDC). 
• Document the quantity of the excess dose in IRT. 
Dose deviations will be tracked as protocol deviations (Section 10.1.6). 
6.9. 
Continued Access to Study Investigational Product After the End of 
the Study  
Study intervention administration consists of a single injection; as such, there will be no access 
to study intervention after the end of the clinical trial. 

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6.10. 
Prior and Concomitant Therapy  
6.10.1. 
Prior Medications  
• Information about prior medications (including any prescription or over-the-counter 
medications, vaccines, or blood products) taken by the participant within the 28 days 
before providing informed consent (or as designated in the inclusion/exclusion 
requirements) will be recorded in the participant’s eCRF. 
• Historical use of facial injections or dermal fillers. 
• Any seasonal influenza vaccine administered during or since September 2022 (for 
Part 1 of the study). 
Any seasonal influenza vaccine administered during or since September 2023 (for 
Part 2 of the study). 
• Any authorized or investigational COVID-19 vaccine at any time before study 
intervention administration. 
6.10.2. 
Concomitant Medications and Therapies  
At study site, study staff must record the following information in the eCRF after questioning 
participants regarding any prohibited or allowed medications taken or non-study vaccinations 
received: 
• All non-study vaccinations administered within the period starting 28 days before the 
study intervention administration and through EoS. 
• All concomitant medications taken through 28 days after study intervention 
administration. Antipyretics and analgesics taken prophylactically (ie, taken in the 
absence of any symptoms in anticipation of an injection reaction) will be recorded as 
such. 
• Systemic steroids (≥10 mg/day of prednisone or equivalent), immunosuppressants, 
immunoglobulins, or long-acting biological therapies that affect immune responses 
(eg, infliximab), or blood products administered at any time during the clinical trial 
period after study intervention administration through EoS. 
• Any concomitant medications used to prevent or treat either COVID-19 or influenza 
through EoS. 
• Antiviral and antiretroviral medications through EoS. 
• Any concomitant medications relevant to or for the treatment of an SAE, AESI, or an 
MAAE from Day 1 through EoS. 
• Any antipyretic or analgesic medications taken to treat or prevent fever or pain, as 
indicated in the participant’s eDiary. 
Concomitant medications (including vaccinations) will be coded using the WHO Drug Global. 

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6.10.3. 
Prohibited Therapy  
The use of the following concomitant medications and/or vaccines will not require withdrawal of 
the participant from the clinical trial but may determine a participant’s evaluability in the per 
protocol (PP) analysis (analysis sets are described in Section 9.3.2): 
• Any investigational or nonregistered product (drug or vaccine) other than the study 
interventions used during the clinical trial period. 
• Immunosuppressants administered during the clinical trial period. For corticosteroids, 
≥10 mg/day of prednisone or equivalent is not permitted. Inhaled, nasal, and topical 
steroids are allowed. 
• An authorized or licensed vaccine administered during the period from 28 days before 
through 28 days after vaccination. 
• Immunoglobulins or long-acting biological therapies that affect immune responses 
(eg, infliximab) or any blood products administered during the clinical trial period. 
• Antiviral and antiretroviral medications. 

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7. 
DELAY OR DISCONTINUATION OF STUDY INTERVENTION 
AND PARTICIPANT DISCONTINUATION/WITHDRAWAL  
Discontinuation of specific sites or of the clinical trial as a whole are detailed in Section 10.1.14. 
7.1. 
Pause Rules  
Study pause rules will be continuously monitored during all periods of the clinical trial by the 
Investigators and the study team, as well as the IST as warranted. The study team or IST may 
request that the clinical trial be paused due to a safety concern, further study intervention will be 
suspended, but all other planned procedures relating to safety, reactogenicity, and 
immunogenicity assessments will continue as described in the study protocol. An unblinded 
statistician will support the determination if study pause rules have been met. The Sponsor will 
notify the Center for Biologics Evaluation and Research within 48 hours in the event of a study 
pause. 
• The occurrence of any of the events listed in Table 7, regardless of treatment group, 
will result in immediate suspension of dosing and enrollment. An unscheduled IST 
will be convened to assess specific data concerns and to make recommendations. 
• The occurrence of safety events listed in Table 7 will pause study intervention 
administration based on defined threshold levels, which are aggregate incidences 
relative to the number of exposed participants within a treatment group. 
Table 7: 
Pause Rule Criteria, Events, and Thresholds  
Pause Rule 
Event 
Number of Participantsa 
Single Event 
1 
Any SAE that cannot be reasonably attributed to 
a cause other than study intervention 
≥1 
2 
Any Grade 4b systemic or local solicited AR that 
cannot be reasonably attributed to a cause other 
than study intervention 
≥1 
3 
Any case of myocarditis and/or pericarditis that 
cannot be reasonably attributed to a cause other 
than study intervention 
≥1 
Proportion of Participants 
4 
Any severe unsolicited nonserious AE that 
cannot be reasonably attributed to a cause other 
than the study intervention (independent of 
within or not within the same system organ class) 
≥2 of the initial 10 participants in 
the same study arm or ≥20% of 
participants within the same study 
arm after the initial 10 participants 
have been dosed 
5 
Any Grade 3 solicited local AR lasting more than 
48 hours that cannot be reasonable attributed to a 
≥2 of the initial 10 participants in 
the same study arm or ≥20% of 
participants within the same study 

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Pause Rule 
Event 
Number of Participantsa 
cause other than the study intervention, starting 
within the 7-day post-injection periodb 
arm after the initial 10 participants 
have been dosedc 
6 
Any Grade 3 solicited systemic AR lasting more 
than 48 hours (24 hours for fever) that cannot be 
reasonably attributed to a cause other than 
vaccination, starting within the 7-day 
post-injection periodb 
≥2 of the initial 10 participants in 
the same study arm or ≥20% of 
participants within the same study 
arm after the initial 10 participants 
have been dosedc 
Abbreviations: AE = adverse event; AR = adverse reaction; FDA = Food and Drug Administration; SAE = serious 
adverse event; US = United States. 
a. 
The rate of AR/AEs will be computed based on the number of exposed participants in each treatment group. For 
solicited AR, participants need to experience the same solicited AR. Unsolicited events will be counted 
independent of within or not within the same system organ class. 
b. 
Grading of parameters will be based on the US FDA Guidance for Industry “Toxicity grading scale for healthy 
adult and adolescent volunteers enrolled in preventive vaccine clinical trials” (DHHS 2007). 
c. 
Reactogenicity eDiary data confirmed by the Investigator as being entered by the participant in error will not 
contribute toward a stopping rule. 
If a pause is triggered in the clinical trial, each participant’s study site visits will continue until 
EoS. If a pause affects a participant’s Vaccination Visit, the window for that participant’s 
Vaccination Visit will be suspended until the pause is lifted and study intervention 
administration can resume. Once the pause is lifted, study intervention administration should be 
reinstated as soon as possible. 
If a participant is in the Screening period for more than 28 days as the result of a pause, the 
participant may be rescreened for study eligibility (and will receive a new Screening number) as 
long as the participant continues to provide consent to participate in the clinical trial. 
7.2. 
Discontinuation of Study Intervention  
Participants who withdraw or are withdrawn from the clinical trial will not be replaced. From an 
analysis perspective, a “withdrawal” from the clinical trial refers to a situation wherein a 
participant does not return for the final visit foreseen in the protocol. 
Participants can withdraw consent and withdraw from the clinical trial at any time, for any 
reason, without prejudice. The Investigator will request that the participant complete all study 
procedures pending at the time of withdrawal. 
If a participant desires to withdraw from the clinical trial because of an AE or pregnancy, the 
Investigator will attempt to obtain agreement to follow-up with the participant until the event is 
considered resolved or stable and will then complete the EoS section of the eCRF. 
All data collected until the date of withdrawal or last contact of the participant will be used for 
the analysis. 
Information relative to the withdrawal will be documented in the eCRF. The Investigator will 
document whether the decision to withdraw a participant from the clinical trial was made by the 
participant, or by the Investigator, as well as which of the following possible reasons was 
responsible for withdrawal: 
• AE 

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• Death 
• Lost to follow-up (LTFU) 
• Other 
• Physician decision 
• Pregnancy 
• Protocol violation 
• Study terminated by Sponsor 
• Withdrawal by participant 
Participants who withdraw from the clinical trial because of AEs (including SAEs or solicited 
ARs) must be clearly distinguished from participants who withdraw for other reasons. 
Investigators will follow-up with participants who withdraw from the clinical trial as a result of 
an AE, SAE, or solicited AR until resolution or stabilization of the event. 
If a participant withdraws from the clinical trial, they may request destruction of any samples 
taken and not tested, and the Investigator must document this in the site study records. 
If the participant withdraws consent for disclosure of future information, the Sponsor may retain 
and continue to use any data collected before such a withdrawal of consent (see Section 10.1.9). 
The Sponsor will continue to retain and use all research results that have already been collected 
for the study evaluation. All biological samples that have already been collected may be retained 
and analyzed at a later date (or as permitted by local regulations). 
7.3. 
Lost to Follow-Up  
A participant will be considered LTFU if the participant repeatedly fails to return for scheduled 
visits and is unable to be contacted by the study site. 
The following actions must be taken if a participant fails to return to the clinic for a required 
study visit: 
• The site must attempt to contact the participant and reschedule the missed visit as 
soon as possible, counsel the participant on the importance of maintaining the 
assigned visit schedule and ascertain whether the participant wishes to and/or should 
continue in the clinical trial. 
• The Investigator or designee must make every effort to regain contact with the 
participant (where possible, 3 telephone calls, and if necessary, a certified letter to the 
participant’s last known mailing address or local equivalent methods). These contact 
attempts should be documented in the participant’s source document. 
If the registered/certified letter is signed by the participant but no other contact is established, the 
participant is considered to be noncompliant with study visits or procedures and will be 
considered to have withdrawn from the clinical trial. 
If due diligence, as described above, has been completed, and the participant continues to be 
unreachable, the participant will be considered LTFU. 

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8. 
STUDY ASSESSMENTS AND PROCEDURES  
Before performing any study procedures, all potential participants will sign an ICF (as detailed in 
Section 10.1.4). Participants will undergo study procedures at the timepoints specified in the SoA 
(Table 1 for Part 1 and Table 2 for Part 2). A participant can also be seen for an unscheduled 
visit at any time during the clinical trial, at the discretion of the Investigator. Reasons for an 
unscheduled visit may include, but are not limited to, reactogenicity issues, symptoms of 
potential ILI and/or COVID-19, or new or ongoing AEs. The site also has the discretion to make 
reminder telephone calls or send text messages to inform the participant about visits, review 
electronic diaries (eDiaries) requirements, or follow-up on ongoing or outstanding issues. 
In accordance with “FDA Guidance on Conduct of Clinical Trials of Medical Products during 
COVID-19 Public Health Emergency,” Investigators may convert study site visits to home visits 
or telemedicine visits with the approval of the Sponsor. Such action should be taken to protect 
the safety and well-being of participants and study site staff or to comply with state or municipal 
mandates. 
General considerations for study assessments and procedures include the following: 
• Protocol waivers or exemptions are not allowed. The study procedures and their 
timing must be followed as presented in the SoA (Table 1 for Part 1 and Table 2 for 
Part 2). Adherence to the study design requirements is essential and required for study 
conduct. 
• Immediate safety concerns should be discussed with the Sponsor immediately upon 
occurrence or awareness to determine if the participant should continue participation 
in the clinical trial. 
• All Screening evaluations must be completed and reviewed to confirm that potential 
participants meet all eligibility criteria. The Investigator will maintain a Screening log 
to record details of all participants screened and to confirm eligibility or record 
reasons for Screening failure, as applicable. 
• In the event of a significant study-continuity issue (eg, caused by a pandemic), 
alternate strategies for participant visits, assessments, medication distribution, and 
monitoring may be implemented by the Sponsor or the Investigator, as per local 
health authority/ethics requirements. 
• The Screening Visit and Day 1 visit will not be performed on the same day for Part 1 
of the study but may be completed on the same day for Part 2. Additionally, the 
Screening Visit assessments may be performed over multiple visits if within the 28-
day Screening window. 
The maximum amount of blood collected from each participant over the duration of the clinical 
trial, including any extra assessments that may be required, will not exceed blood limits specified 
by local regulations. 
Repeat or unscheduled samples may be taken for safety reasons or for technical issues with the 
samples. Further details are provided in both the ICF and Laboratory Reference Manual. 

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8.1. 
Demography  
Demographic information relating to the participant’s sex, age, and race will be recorded at 
Screening in the EDC. 
Medical history of each participant will be collected and recorded in the EDC. Clinically 
significant findings that were present prior to the signature of the informed consent will also be 
included in EDC. 
8.2. 
Immunogenicity Assessments  
8.2.1. 
Part 1 (Phase 1/2)  
Planned timepoints for all immunogenicity assessments are provided in the SoA. The following 
analytes will be measured: 
• Influenza: Serum antibody level as measured by HAI assay and potentially serum 
neutralizing antibody (nAb) level as measured by microneutralization assay. 
• SARS-CoV-2: Serum nAb titers as measured by pseudovirus neutralization assay 
(PsVNA) assay and potentially serum binding antibody titers by enzyme-linked 
immunosorbent assay or multiplex assay specific to the SARS-CoV-2 proteins. 
• Cellular immunogenicity in a subset of participants. 
This clinical trial is not powered for efficacy assessment, but any reports of clinical influenza or 
COVID-19 will be summarized by study group as an exploratory descriptive analysis. 
8.2.2. 
Part 2 (Phase 2 Extension)  
Planned timepoints for all immunogenicity assessments are provided in the SoA. The following 
analytes will be measured: 
• Influenza: Serum antibody level as measured by HAI assay and potentially serum 
neutralizing antibody (nAb) level as measured by microneutralization assay. 
• SARS-CoV-2: Serum nAb titers as measured by pseudovirus neutralization assay 
(PsVNA) assay and potentially serum binding antibody titers by enzyme-linked 
immunosorbent assay or multiplex assay specific to the SARS-CoV-2 proteins. 
8.3. 
Safety Assessments  
8.3.1. 
Part 1 (Phase 1/2)  
Safety assessments will include monitoring and recording of the following for each participant 
according to the SoA: 
• Solicited local and systemic ARs that occur during the 7 days following study 
intervention administration (ie, the day of injection and 6 subsequent days). Solicited 
ARs will be recorded daily using eDiaries. 

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• Unsolicited AEs observed or reported during the 28 days following study intervention 
administration (ie, the day of injection and 27 subsequent days). Unsolicited AEs are 
AEs that are not included in the protocol-defined solicited ARs. 
• Unsolicited AEs leading to discontinuation from dosing and/or study participation 
from Day 1 through EoS or discontinuation from the clinical trial. 
• Unsolicited MAAEs from Day 1 through EoS or discontinuation from the clinical 
trial. 
• SAEs from Day 1 through EoS or discontinuation from the clinical trial. 
• Unsolicited AESIs from Day 1 through EoS or discontinuation from the clinical trial. 
• Details of all pregnancies in participants will be collected postinjection and until the 
end of their participation in the clinical trial. All pregnancies must be followed to 
determine the outcome; however, pregnancy-related data received after the end of the 
clinical trial may not be collected in the clinical database. 
• Results of safety laboratory tests. 
• Vital sign measurements. 
• Physical examination findings. 
• Concomitant medications and nonstudy vaccinations. 
• For participants ≥18 to <51 years of age only: 12-lead electrocardiogram (ECG) 
obtained at Visit 1/Day 1 prior to injection. 
Planned timepoints for all safety assessments are provided in the SoA (Table 1). 
8.3.2. 
Part 2 (Phase 2 Extension)  
Safety assessments will include monitoring and recording of the following for each participant 
according to the SoA: 
• Solicited local and systemic ARs that occur during the 7 days following study 
intervention administration (ie, the day of injection and 6 subsequent days). Solicited 
ARs will be recorded daily using eDiaries. 
• Unsolicited AEs observed or reported during the 28 days following study intervention 
administration (ie, the day of injection and 27 subsequent days). Unsolicited AEs are 
AEs that are not included in the protocol-defined solicited ARs. 
• Unsolicited AEs leading to discontinuation from dosing and/or study participation 
from Day 1 through EoS or discontinuation from the clinical trial. 
• Unsolicited MAAEs from Day 1 through EoS or discontinuation from the clinical 
trial. 
• SAEs from Day 1 through EoS or discontinuation from the clinical trial. 
• Unsolicited AESIs from Day 1 through EoS or discontinuation from the clinical trial. 

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• Details of all pregnancies in participants will be collected postinjection and until the 
end of their participation in the clinical trial. All pregnancies must be followed to 
determine the outcome; however, pregnancy-related data received after the end of the 
clinical trial may not be collected in the clinical database. 
• Vital sign measurements. 
• Physical examination findings. 
• Concomitant medications and nonstudy vaccinations. 
• 12-lead ECG obtained at Visit 1/Day 1 prior to injection. 
Planned timepoints for all safety assessments are provided in the SoA (Table 2). 
8.3.3. 
Physical Examinations (Part 1 and Part 2)  
• A complete physical examination will include, at a minimum, assessments of skin, 
head, ears, eyes, nose, throat, neck, thyroid, lungs, heart, cardiovascular system, 
abdomen, lymph nodes, musculoskeletal system, and extremities. Height and weight 
will also be measured and recorded. At Screening, the BMI will be calculated using 
the formula weight (kg) / (height [m])2. 
• On the day of injection (Day 1), prior to injection, axillary lymph nodes of the 
injection arm(s) will be examined, and any abnormalities will be documented. 
• Symptom-directed physical examinations will be performed at all clinic visits, except 
at Screening, where a full examination will be performed. Interim physical 
examinations will be performed at the discretion of the Investigator. Any clinically 
significant finding identified by an HCP during postinjection study visits should be 
reported as an AE. Investigators should also pay special attention to clinical signs 
related to previous serious illnesses. 
8.3.4. 
Vital Signs (Part 1 and Part 2)  
Vital sign measurements will include systolic and diastolic blood pressure, heart rate, respiratory 
rate, and body temperature (preferred route is oral). The participant will be seated for at least 
5 minutes before all measurements are taken. Vital signs will be measured at the timepoints 
indicated in the SoA (Table 1 and Table 2). On the day of study intervention administration, vital 
sign measurements will be collected once before and at least 60 minutes after study intervention. 
Vital signs may be collected at other study visits in conjunction with a symptom-directed 
physical examination. 
Following injection, any abnormal vital sign measurement should be assessed by the Investigator 
to determine if it meets AE reporting criteria PP and reported as an AE in EDC, if appropriate. 
The Investigator will continue to monitor the participant with additional assessments until the 
vital sign value has reached the reference range, returns to the vital sign value at Baseline, is 
considered stable, or until the Investigator determines that follow-up is no longer medically 
necessary. 
Participants who are febrile (body temperature ≥38.0°C/100.4°F) before injection on Day 1 
should be rescheduled within the relevant window period to receive the injection. Participants 

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who are afebrile with minor illnesses may be administered study intervention at the discretion of 
the Investigator. 
When procedures overlap and are scheduled to occur at the same timepoint, the order of 
procedures should be vital sign measurements and then blood collection. 
8.3.5. 
Electrocardiograms (Part 1 and Part 2)  
For participants aged ≥18 to <51 only, a 12-lead ECG will be obtained, after 10 minutes of 
supine rest, as outlined in the SoA (Table 1 and Table 2). Skin preparation should be thorough 
and electrode placement should be according to standard 12-lead ECG procedure. The purpose of 
the ECG is to serve as a Baseline comparison, should it be necessary, for subsequent clinical 
evaluation of suspected myocarditis and/or pericarditis. The ECG output should be filed in the 
participant’s binder, and the Investigator will not be expected to document an ECG reading. 
Central reading of the ECG will not be performed. Clinically significant abnormal ECG findings, 
if incidentally observed by the Investigator, may contribute to Investigator’s assessment of 
eligibility, at his or her discretion, as per Part 1 Exclusion Criterion 3 and Part 2 
Exclusion Criterion 3. 
8.3.6. 
Clinical Safety Laboratory Tests (Part 1) 
All protocol-required laboratory tests, as defined in Section 10.2, must be conducted in 
accordance with the laboratory manual and the SoA (Table 1). 
Safety laboratory tests will consist of white blood cell count, hemoglobin, hematocrit, platelets, 
AST, ALT, creatinine, alkaline phosphatase, and total bilirubin. 
Additional blood samples for safety laboratory tests may be taken at the discretion of the 
Investigator if warranted to ensure participant’s safety. 
• The Investigator must review the laboratory results, document this review, and record 
any clinically significant changes occurring during the clinical trial as an AE. The 
laboratory results must be retained with source documents. 
• All Screening laboratory results must be reviewed prior to dosing of any study 
intervention to ensure that the participant’s laboratory values meet all inclusion and 
exclusion criteria. 
• All laboratory tests with values considered clinically significantly abnormal during 
participation in the clinical trial should be repeated until the values return to normal 
or Baseline or are no longer considered clinically significant by the Investigator or 
medical monitor. If clinically significant abnormal values do not return to 
normal/Baseline within a period of time judged reasonable by the Investigator, the 
etiology should be identified, and the Sponsor notified. 
8.3.7. 
Assessment for Respiratory Viral Infection  
8.3.7.1. 
Part 1 (Phase 1/2)  
During the clinical trial, participants might experience symptoms consistent with ILI or 
SARS-CoV-2 infection. All participants will provide nasal swab samples before the injection on 

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Day 1 for assessment of infection with respiratory pathogens, including influenza viruses and 
SARS-CoV-2, as influenza or COVID-19 symptoms may confound reactogenicity assessments. 
Throughout the clinical trial, the participant will be instructed to contact the study site if they 
have symptoms suggestive of ILI (Section 10.3.7) or SARS-CoV-2 (Section 10.3.8). An 
unscheduled visit for symptom assessment and nasal swab for viral respiratory pathogens will be 
conducted within 7 days of the onset of any potential ILI or SARS-CoV-2 symptoms. 
Planned timepoints for all safety and immunogenicity assessments are provided in the SoA 
(Table 1). 
8.3.7.2. 
Part 2 (Phase 2 Extension)  
All participants will provide nasal swab samples before the injection on Day 1 for assessment of 
infection with respiratory pathogens, including influenza viruses and SARS-CoV-2, as influenza 
or COVID-19 symptoms may confound reactogenicity assessments. 
8.3.8. 
Pregnancy Testing (Part 1 and Part 2)  
Participants who have a positive pregnancy test at Screening must not be enrolled. 
Planned timepoints for pregnancy testing are provided in the SoA (Table 1 and Table 2). 
For participants of childbearing potential, a point-of-care urine pregnancy test will be performed 
at the Screening Visit and before injection. At the discretion of the Investigator, a pregnancy test 
either via blood or point-of-care urine can be performed at any time. For participants of 
nonchildbearing potential, the FSH level may be measured at the Screening Visit, as necessary, 
and at the discretion of the Investigator, to confirm menopausal status (please see Section 10.6 
for details). 
Additional pregnancy testing during the clinical trial may also be performed if required by local 
regulatory requirements. 
8.3.9. 
Safety Telephone Calls (Part 1 and Part 2) 
A safety telephone call is a telephone call made to the participant by trained site personnel. This 
call will follow a script, which will facilitate the collection of relevant safety information. Safety 
telephone calls will follow a schedule for each participant, as shown in the SoA (Table 1 and 
Table 2). The participant will be interviewed according to the script about occurrence of AEs, 
MAAEs, SAEs, AESIs, AEs leading to discontinuation from study participation, concomitant 
medications associated with those events, and any nonstudy vaccinations. All safety information 
collected from the phone call must be documented in the source documents as described by the 
participant and not documented on the script used for the phone call. An unscheduled follow-up 
safety call may be triggered if an eDiary record results in identification of a relevant safety event. 
A safety telephone call may trigger an unscheduled visit. 
8.3.10. 
Electronic Diaries (Part 1 and Part 2)  
At the time of consent, participants must confirm they will be willing to complete an eDiary 
using either an application downloaded to their smartphone or a device that will be provided at 
the time of enrollment. The eDiary will be the only source document allowed for solicited 
systemic or local ARs (including body temperature measurements). 

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Before enrollment on Day 1, the participant will be instructed to download the eDiary 
application or will be provided with an eDiary device to record solicited ARs (Section 10.3.3) on 
Day 1. Participants will be instructed to complete eDiary entries daily. Quantitative temperature 
recordings and measurement of any injection site erythema or swelling/induration reported on 
the following day may be excluded from the analyses of solicited ARs. 
On Day 1 (dosing day), study sites will distribute Sponsor-provided oral thermometers and rulers 
for use by participants to assess body temperature and injection site reactions, respectively, for 
recording solicited ARs in the eDiaries. Based on availability, smartphone devices may be 
provided to those participants who do not have their own device to use for eDiary activities. 
On Day 1 (injection day), participants will activate their eDiary and record data into the eDiary 
starting approximately 1 hour after the injection under supervision of the study site staff to 
ensure successful entry of assessments. The study site staff will perform any retraining as 
necessary. Participants will continue to record data in the eDiary after they leave the study site, 
preferably in the evening and at the same time each day, on the day of study intervention 
administration and for 6 days following study intervention administration, for a total of 7 days. 
Participants will record the following data in the eDiary during the 7 days following study 
intervention administration: 
• Solicited local and systemic ARs (Section 10.3.3). ARs beyond Day 7 should be 
reviewed either during the next scheduled telephone call or at the following study site 
visit. 
• Daily oral body temperature measurement should be performed at approximately the 
same time each day using the thermometer provided by the study site. If body 
temperature is taken more than once in a given day, only the highest temperature 
reading should be recorded. 
• Other measurements, as applicable, for solicited local ARs (injection site erythema 
and swelling/induration) will be performed using the ruler provided by the study site. 
• Any medications taken to treat or prevent pain or fever. 
Study site staff (or delegate) will review all eDiary data with participants during the Day 8 visit 
(Visit 2) after vaccination. However, if a Grade 3 or Grade 4 AR is reported at any time during 
the first 7 days after vaccination, the site will contact the participant in sufficient time to 
determine if a potential pause rule has been met (as per Section 7.1). The sites should have a 
process in place for monitoring and follow-up of potential pause rule events on nonbusiness days 
while dosing is actively taking place on the study. The site should report potential pause rule 
events or to make clarifications in the EDC when there are discrepancies between the 
participant’s reported Grade 3 or above solicited AR on eDiary and the site’s assessment. 
8.4. 
Adverse Events, Serious Adverse Events, and Other Safety 
Reporting  
The definitions of AEs and SAEs can be found in Section 10.3.1 and Section 10.3.2, 
respectively. The definitions of unsolicited and solicited adverse events, as well as MAAEs, are 
found in Section 10.3.3 and Section 10.3.4, respectively. The definition of AESI can be found in 
Section 10.3.6. 

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The Investigator and any qualified designees are responsible for detecting, documenting, and 
recording events that meet the definition of an AE or SAE and remain responsible for following 
up all AEs that are serious, of special interest, considered related to the study intervention or 
study procedures, or that caused the participant to discontinue the clinical trial. The method of 
recording, evaluating, and assessing causality of AEs and SAEs and the procedures for 
completing and transmitting SAE reports are provided in Section 10.3. 
8.4.1. 
Time Period and Frequency for Collecting AE and SAE Information  
All unsolicited AEs will be collected from the day of study intervention administration through 
28 days postinjection. 
All AEs leading to study discontinuation, MAAE, SAEs, and AESIs will be collected from the 
start of study intervention administration until EoS visit at the timepoints specified in the SoA 
(Table 1 and Table 2). 
All SAEs and AESIs will be recorded and reported to the Sponsor or designee immediately, and 
under no circumstance should this exceed 24 hours of becoming aware of the event via the EDC. 
If a site receives a report of a new SAE or AESI from a study participant or receives updated 
data on a previously reported SAE or AESI and the eCRF has been taken offline, then the site 
can report this information on a paper SAE/AESI form via the contact information provided on 
the form (Section 10.3.10). 
An abnormal value or result from a clinical or laboratory evaluation can also indicate an AE if it 
is determined by the Investigator to be clinically significant. If this is the case, it must be 
recorded in the source document and as an AE on the appropriate AE form(s). The evaluation 
that produced the value or result should be repeated until that value or result returns to 
normal/Baseline or is stabilized and the participant’s safety is not at risk. 
Investigators are not obligated to actively seek AEs or SAEs after EoS participation. However, if 
the Investigator learns of any SAE at any time after a participant has withdrawn from or 
completed the clinical trial and the Investigator considers the event to be reasonably related to 
the study intervention administration or study participation, the Investigator must promptly 
notify the Sponsor. 
Active and passive surveillance for ILI and COVID-19 will be conducted from Day 1 through 
EoS. Participants who develop ILI or COVID-19 will be followed through 30 days from the 
onset of ILI, even if Day 30 is beyond EoS. 
Medical occurrences that begin before the start of study intervention but after obtaining informed 
consent will be recorded as medical history/current medical conditions, not as AEs; however, if 
the condition worsens at any time during the clinical trial, it will be recorded and reported as an 
AE. 
8.4.2. 
Method of Detecting AEs and SAEs  
Care will be taken not to introduce bias when detecting AEs and/or SAEs. Open-ended and 
nonleading verbal questioning of the participant is the preferred method to inquire about 
AE occurrences. 

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AEs may be collected as follows: 
• Observing the participant. 
• Receiving an unsolicited complaint from the participant. 
• Questioning the participant in an unbiased and nonleading manner. 
8.4.3. 
Eliciting and Documenting Adverse Events  
The Investigator is responsible for documenting AEs regardless of study arm or suspected causal 
relationship to study intervention. For all AEs, the Investigator must pursue and obtain 
information adequate to determine the outcome of the AE and to assess whether the AE meets 
the criteria for classification as an SAE requiring immediate notification to the Sponsor or its 
designated representative. 
At every study site visit or telephone contact, participants will be asked if they had any changes 
in their health or illnesses (including ILI and COVID-19 symptoms) according to the scripts 
provided. Participants will also be asked if they have been hospitalized, had any accidents, used 
any new medications, changed concomitant medication regimens (both prescription and over-
the-counter medications), or had any nonstudy vaccinations. 
In addition to participant observations, physical examination findings or data relevant to 
participant safety that are classified as AEs will be documented on the AE page of the eCRF. 
After the initial AE/SAE report, the Investigator is required to proactively follow each 
participant at subsequent visits/contacts. All AEs and SAEs will be treated as medically 
appropriate and followed until resolution, stabilization, the event is otherwise explained, or the 
participant is LTFU (as defined in Section 7.3). All contacts, or contact attempts, concerning 
follow-up of AEs/SAEs should be recorded in the participant’s source documentation. 
8.4.4. 
Regulatory Reporting Requirements for SAEs  
Prompt notification by the Investigator to the Sponsor of an SAE is essential so that legal 
obligations and ethical responsibilities toward the safety of participants and the safety of a study 
intervention under clinical investigation are met. 
The Sponsor has a legal responsibility to notify both the local regulatory authority and other 
regulatory agencies about the safety of a study intervention under clinical investigation. The 
Sponsor will comply with country-specific regulatory requirements relating to safety reporting to 
the regulatory authority, IRB or IEC, and Investigators. 
Investigator safety reports must be prepared for suspected unexpected SAEs (SUSAR) according 
to local regulatory requirements and Sponsor policy and forwarded to Investigators as necessary. 
An Investigator who receives an Investigator Safety Report describing an SAE or other specific 
safety information (eg, summary or listing of SAEs) from the Sponsor will review and then file it 
along with the IB and will notify their local IRB/IEC if appropriate according to local 
requirements. 

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8.4.5. 
Pregnancy  
Details of all participant pregnancies will be collected after the start of study intervention. 
Participants who become pregnant at any time during the clinical trial should remain in the 
clinical trial and complete all study visits as scheduled. 
Abnormal pregnancy outcomes (eg, spontaneous abortion, fetal death, stillbirth, congenital 
anomalies, ectopic pregnancy) will be considered as SAEs. The Investigator must immediately 
report to the Sponsor any pregnancy resulting in an abnormal outcome according to the 
procedures described for SAEs. 
Pregnancies occurring in participants after enrollment must be reported to Sponsor or designee 
within 24 hours of the site learning of its occurrence, using the SAE Mailbox or the SAE Fax 
line (Section 10.3.10). If the participant agrees to submit this information, the pregnancy must be 
followed to determine the outcome. This follow-up should occur even if intended duration of the 
safety follow-up for the clinical trial has ended. Pregnancy report forms will be distributed to the 
study site to be used for this purpose. 
8.5. 
Pharmacokinetics  
Pharmacokinetic parameters are not evaluated in this clinical trial. 
8.6. 
Pharmacodynamics  
Pharmacodynamic parameters are not evaluated in this clinical trial. 
8.7. 
Genetics  
A prospective research sample, to be used for future genetic research, will be collected from 
participants who have consented to participate in the genetic analysis component of the clinical 
trial. Participation is optional. Participants who do not wish to participate in the genetic research 
may still participate in the clinical trial. 
The ICF will contain a separate consent form that addresses the use of this sample. 
8.8. 
Biomarkers  
Transcriptomic and genomic samples will be part of the optional biomarker assessment as per the 
SoA once consented by the study participant. Exploratory assessments may include assessment 
of biomarkers for safety, reactogenicity, and inflammation. Serologic markers of disease 
severity, immune response to SARS-CoV-2 or influenza, reverse transcription polymerase chain 
reaction (RT-PCR) of nasal swab samples, genetic sequences of SARS-CoV-2 or influenza 
strains isolated from participants’ samples, and genomic and transcriptomic samples may also be 
evaluated. Samples will be collected according to the schedule described in the SoA (Table 1 and 
Table 2) and as detailed in the laboratory manual provided separately to sites. 
Plasma and serum samples for potential cardiac biomarker analysis will be collected and banked 
from participants ≥18 to <51 years of age according to the schedule described in the SoA 
(Table 1 and Table 2) and as detailed in the laboratory manual provided separately to sites. If 
indicated, and requested by ModernaTX, testing of cardiac biomarkers may be performed. 

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The Sponsor may store samples for the time period specified in the ICF to achieve study 
objectives. Additionally, with participants’ consent, samples may be used for further research by 
the Sponsor or in collaboration with others such as universities or other companies to contribute 
to the understanding of vaccine response or other diseases, the development of related or new 
treatments, or research methods. 
8.9. 
Health Economics or Medical Resource Utilization and Health 
Economics  
Health economics or Medical resource utilization and health economics parameters are not 
evaluated in this clinical trial. 

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9. 
STATISTICAL CONSIDERATIONS  
This section summarizes the planned statistical analysis strategy and procedures for the clinical 
trial. The details of the statistical analyses will be provided in the statistical analysis plan (SAP). 
If, after the clinical trial has begun, but prior to any unblinding, changes are made to primary 
objectives/hypotheses, or the statistical methods related to those hypotheses, then the protocol 
will be amended (consistent with ICH Guideline E9). Changes to other secondary or exploratory 
analyses made after the protocol has been finalized, along with an explanation as to when and 
why they occurred, will be listed in the SAP or CSR for the clinical trial. Ad hoc exploratory 
analyses, if any, will be clearly identified in the CSR. 
9.1. 
Blinding and Responsibility for Analyses  
This is an observer-blind clinical trial. The Investigator, study staff, study participants, site 
monitors, and Sponsor personnel (or its designees) will be blinded to the study intervention 
administered until the study database is locked and unblinded, with the following exceptions: 
• Unblinded personnel (of limited number) will be assigned to vaccine accountability 
procedures and will prepare the study intervention for all participants. These 
personnel will have no study functions other than study intervention management, 
documentation, accountability, preparation, and administration. They will not be 
involved in participant evaluations and will not reveal the identity of the study 
intervention to either the participant or the blinded study site personnel involved in 
the conduct of the clinical trial unless this information is necessary in the case of an 
emergency. 
• Unblinded medically qualified study site personnel will administer the study 
intervention. They will not be involved in assessments of any study endpoints. 
• Unblinded site monitors, not involved in other aspects of monitoring, will be assigned 
as the study intervention accountability monitors. They will have responsibilities to 
ensure that sites are following all proper study intervention accountability, 
preparation, and administration procedures. 
• An independent unblinded statistical and programming team will perform the 
preplanned interim analysis (Section 9.6). Sponsor team members will be prespecified 
to be unblinded to the interim analysis results and will not communicate the results to 
the blinded Investigators, study site staff, clinical monitors, or participants. 
• The IST will review unblinded safety data provided by the independent unblinded 
statistician to safeguard the interests of clinical study participants and to help ensure 
the integrity of the clinical trial. The IST will review unblinded statistical outputs for 
ad hoc safety reviews triggered by pause rules, should this occur. Section 10.5 
provides additional information on IST and safety review. 
The treatment assignment, including the injection site and the corresponding vaccine 
administered, will be concealed by having the unblinded pharmacy personnel prepare the study 
intervention in a secure location that is not accessible or visible to other study staff. An opaque 
sleeve over the syringe used for injection will maintain the blind at the time of injection. Only 
delegated unblinded study site staff will conduct the injection procedure. Once the injection is 

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completed, only the blinded study staff will perform further assessments and interact with the 
participants. Access to the randomization code will be strictly controlled at the pharmacy. 
9.2. 
Statistical Hypotheses  
This clinical trial does not have formal statistical hypothesis testing planned for the primary 
objectives (safety and reactogenicity). The total sample sizes planned for Part 1 and Part 2 are 
considered sufficient to provide descriptive summary of the safety and reactogenicity across 
study treatment arms within each age Cohort for respective parts. 
9.3. 
Sample Size Determination  
9.3.1. 
Part 1  
Approximately 1224 participants will be enrolled at an evenly allocated ratio across the 
12 treatment arms in Cohort A for adults ≥65 to <80 years of age and 12 treatment arms in 
Cohort B for adults ≥18 to <65 years of aged, with 50 participants planned for each arm in 
Cohort A (600 participants in total) and 52 participants planned for each arm in Cohort B 
(624 participants in total) (Table 8). Approximately 50 participants in each group receiving an 
investigational injection have approximately 87% (or 92%) probability to observe at least 
1 participant with an AE given the true underlying incidence rate of AE is 4% (or 5%). 
Table 8: 
Probability of AEs Based on Sample Size(Part 1)  
n 
True AE Rate 
Probability of 0 AE 
Probability of at Least 1 AE Observed 
50 
2.0% 
36.4% 
63.6% 
50 
3.0% 
21.8% 
78.2% 
50 
4.0% 
13.0% 
87.0% 
50 
5.0% 
7.7% 
92.3% 
9.3.2. 
Part 2  
Approximately, 520 participants will be enrolled at an evenly allocated ratio across the 
13 treatment arms in Part 2 for adults ≥18 to <50 years of age, with 40 participants planned for 
each arm. Approximately 40 participants in each group receiving an investigational injection 
have approximately 80.5% (or 87.1%) probability to observe at least 1 participant with an AE 
given the true underlying incidence rate of AE is 4% (or 5%). 
Table 9: 
Probability of AEs Based on Sample Size (Part 2)  
n 
True AE Rate 
Probability of 0 AE 
Probability of at Least 1 AE Observed 
40 
2.0% 
44.6% 
55.4% 
40 
3.0% 
29.6% 
70.4% 
40 
4.0% 
19.5% 
80.5% 
40 
5.0% 
12.9% 
87.1% 

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9.4. 
Analysis Sets  
For the purposes of analysis, the following analysis sets are defined in Table 10. 
Table 10: 
Populations for Analyses  
Analysis Sets 
Description 
Randomization Set 
The randomization set consists of all participants who are randomly 
assigned. 
Full Analysis Seta 
The FAS consists of all participants who are randomly assigned and 
receive the study intervention. 
Per Protocol Setb 
The PP Set consists of all participants in the FAS who comply with the 
injection schedule, comply with the timings of immunogenicity blood 
sampling to have a Baseline and at least 1 post-injection assessment at 
Day 29, have no documented infection (confirmed by RT-PCR test) of 
either influenza or SARS-CoV-2 on Day 1 and up to Day 29, and have 
no major protocol deviations that affect the immune response. 
Safety Setc 
The Safety Set consists of all participants who are randomly assigned 
and receive the study intervention. 
Solicited Safety Setd 
The Solicited Safety Set consists of all participants in the Safety Set who 
contribute any solicited AR data. 
Abbreviations: AR = adverse reaction; FAS = full analysis set; PP = per protocol; RT-PCR = reverse transcription 
polymerase chain reaction; SARS-CoV 2 = severe acute respiratory syndrome coronavirus 2. 
a. 
For the FAS, participants will be analyzed according to the group to which they were randomized. 
b. 
The PP Set will be used as the primary analysis set for analyses of immunogenicity unless otherwise specified. 
Participants will be analyzed according to the group to which they were randomized. 
c. 
The Safety Set will be used for all analyses of safety, except for the solicited ARs. Participants will be included 
in the treatment group corresponding to what they actually received. 
d. 
The Solicited Safety Set will be used for the analyses of solicited ARs, and participants will be included in the 
treatment group corresponding to what they actually received. 
9.5. 
Statistical Analyses  
The statistical analyses in this clinical trial will be planned and performed on the data collected. 
The SAP will be developed and finalized before the interim analyses. The SAP will describe the 
preplanned statistical analysis details and the participant populations to be included in the 
analyses. This section is a summary of the planned statistical analyses of the primary and 
secondary endpoints. 
9.5.1. 
Immunogenicity Analyses  
The analysis population of immunogenicity will be the PP Set. 
For the immunogenicity endpoints, geometric mean of specific antibody titers with 
corresponding 95% confidence interval (CI) at each timepoint and geometric mean fold rise 
(GMFR) of specific antibody titers with corresponding 95% CI at each post-Baseline timepoint 
over pre-injection Baseline at Day 1 will be provided by treatment arm. Descriptive summary 
statistics including median, minimum, and maximum will also be provided. 

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For participants in the groups receiving mRNA-1083, mRNA-1010 or influenza injections, 
seroconversion rate from Baseline will be provided with a 2-sided 95% CI using the Clopper-
Pearson method at each post-Baseline timepoint. Rate of seroconversion is defined as the 
proportion of participants with either a pre-injection HAI titer 
 and a post-injection HAI 
titer 
, or a pre-injection HAI titer 
 and a minimum 4-fold rise in post-injection HAI 
antibody titer. 
For participants in the groups receiving mRNA-1083, mRNA-1283, or mRNA-1273 injections, 
seroresponse is defined as either participants with GMFR in nAb titers of ≥4-fold at Day 29 
compared with Day 1 in those with Baseline titer ≥LLOQ, or Day 29 titer ≥4 × LLOQ if 
Baseline titer is <LLOQ. 
Between-group comparisons will be evaluated for the immunogenicity endpoints (GMT and 
seroconversion/seroresponse rate difference) in the PP Set; details will be provided in the SAP. 
9.5.2. 
Efficacy Analyses (Part 1 Only) 
Analyses of RT-PCR-confirmed protocol-defined ILI and RT-PCR-confirmed symptomatic 
SARS-CoV-2 (COVID-19) will be performed on the FAS. The participants will be summarized 
according to the study treatment groups to which they are randomized into. 
Frequency of RT-PCR-confirmed protocol-defined ILI and RT-PCR-confirmed symptomatic 
SARS-CoV-2 observed among the participants in the FAS will be summarized according to the 
treatment groups as randomized. 
9.5.3. 
Safety Analyses  
All safety analyses will be based on the Safety Set, except summaries of solicited ARs, which 
will be based on the Solicited Safety Set. All safety analyses will be provided by treatment 
group. Participants will be included in the treatment group corresponding to what they actually 
received. 
Safety and reactogenicity will be assessed by clinical review of all relevant parameters, including 
solicited ARs (local and systemic events), unsolicited AEs, SAEs, AESIs, MAAEs, severe AEs, 
and AEs leading to withdrawal from study participation. 
The number and percentage of participants with any solicited local AR, solicited systemic AR, 
and solicited AR during the 7-day follow-up period after the injection will be summarized. A 
2-sided 95% exact CI using the Clopper-Pearson method will also be provided for the percentage 
of participants with any solicited AR. 
The number and percentage of participants with unsolicited AEs, SAEs, AESIs, MAAEs, severe 
AEs, and AEs leading to withdrawal from study participation will be summarized. Unsolicited 
AEs will be coded according to Medical Dictionary for Regulatory Activities (MedDRA) and 
presented by MedDRA system organ class (SOC) and preferred term (PT). 
Solicited ARs will be coded by SOC and PT according to the MedDRA for AR terminology. The 
Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive 
Vaccine Clinical Trials (DHHS 2007) will be used in this clinical trial with modification for rash, 
solicited ARs, and vital signs. 
CCI
CCI
CCI

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The number of events of unsolicited AEs, SAEs, AESIs, MAAEs, severe AEs, and AEs leading 
to withdrawal from study participation will be reported in summarization tables accordingly. 
Table 11 summarizes the analysis strategy for safety parameters. For all other safety parameters, 
descriptive summary statistics will be provided. Further details will be described in the SAP. 
Table 11: 
Analysis Strategy for Safety Parameters  
Safety Endpoint 
Number and 
Percentage of 
Participants 
Number 
of 
Events 
95% 
CI 
Any solicited AR (overall and by local, systemic) 
 
– 
 
Any unsolicited AE 
 
 
– 
Any unsolicited treatment-related AE 
 
 
– 
Any SAE 
 
 
– 
Any treatment-related SAE 
 
 
– 
Any unsolicited AESI 
 
 
– 
Any unsolicited treatment-related AESI 
 
 
– 
Any unsolicited MAAE 
 
 
– 
Any unsolicited treatment-related MAAE 
 
 
– 
Any unsolicited severe AE 
 
 
– 
Any unsolicited treatment-related severe AE 
 
 
– 
Any unsolicited AE leading to withdrawal from study 
participation 
 
 
– 
Abbreviations: AE = adverse event; AESI = adverse event of special interest; AR = adverse reaction; 
CI = confidence interval; MAAE = medically attended adverse event; SAE = serious adverse event. 
Notes: 95% CI using the Clopper-Pearson method, =results will be provided. 
9.5.4. 
Exploratory Analyses  
Analyses of the exploratory endpoints (if any) will be described in the SAP. 
9.6. 
Planned Analyses  
The analysis for each part of the study (Part 1 and Part 2), will be performed independently and 
reported in a separate CSR. 
Part 1: 
An interim analysis of safety, reactogenicity, and immunogenicity is planned after all the 
participants in Cohort A and B have completed the Day 29 visit. 
In addition, another interim analysis for reactogenicity only may be performed after all the 
participants in Cohort A and B have completed the Day 8 visit. 
The potential interim analysis as of completion of Day 8 may be performed by an independent 
team of unblinded statistician and programmers. The interim analysis as of completion of Day 29 
will be performed by the study statistician and programmers. The group-level unblinded 
summary data of the interim analyses may be reviewed by the Sponsor project team for safety 

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monitoring and/or clinical development planning purposes for the mRNA-1083 project. More 
details will be documented in the study data blinding plan. 
The final analysis of Part 1 will be performed after all the participants in both Cohort A and 
Cohort B in Part 1 have completed the Day 181/EoS visit. 
Part 2: 
An interim analysis of safety, reactogenicity, and immunogenicity is planned after all 
participants have completed the Day 29 visit. 
The interim analysis as of completion of Day 29 will be performed by the study statistician and 
programmers. The group-level unblinded summary data of the interim analyses may be reviewed 
by the Sponsor project team for safety monitoring and/or clinical development planning purposes 
for the mRNA-1083 project. More details will be documented in the study data blinding plan. 
The final analysis of Part 2 will be performed after all participants in Part 2 have completed the 
Day 181/EoS visit. 
9.6.1. 
Multiplicity  
No multiplicity adjustment will be needed for either within each of the interim and final analyses 
or between the interim analyses and the final analysis because there will not be formal statistical 
hypothesis testing planned for the primary objective (safety and reactogenicity) and the interim 
and final analyses will be based on descriptive summaries using observed data. 

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10. 
SUPPORTING DOCUMENTATION AND OPERATIONAL 
CONSIDERATIONS  
10.1. 
Appendix 1: Regulatory, Ethical, and Study Oversight 
Considerations  
10.1.1. 
Regulatory and Ethical Considerations  
This clinical trial will be conducted in accordance with the protocol and with the following: 
• Consensus ethical principles derived from international guidelines including the 
Declaration of Helsinki and Council for International Organizations of Medical 
Sciences international ethical guidelines. 
• Applicable ICH GCP guidelines. 
• Applicable laws and regulations. 
The protocol, protocol amendments, ICF, IB, and other relevant documents (eg, advertisements) 
must be submitted to an IRB/IEC by the Investigator and reviewed and approved by the IRB/IEC 
before the clinical trial is initiated. 
Any amendments to the protocol will require IRB/IEC approval before implementation of 
changes made to the study design, except for changes necessary to eliminate an immediate 
hazard to study participants. 
Protocols and any substantial amendments to the protocol will require health authority approval 
prior to initiation except for changes necessary to eliminate an immediate hazard to study 
participants. 
The Investigator will be responsible for the following, as applicable: 
• Providing written summaries of the status of the clinical trial to the IRB/IEC annually 
or more frequently in accordance with the requirements, policies, and procedures 
established by the IRB/IEC. 
• Notifying the IRB/IEC of SAEs or other significant safety findings as required by 
IRB/IEC procedures. 
• Providing oversight of the conduct of the clinical trial at the site and adherence to 
requirements of 21 CFR, ICH guidelines, the IRB/IEC, European regulation 536/2014 
for clinical studies, and all other applicable local regulations. 
10.1.2. 
Audits and Inspections  
The Sponsor, their designee(s), the IRB, or regulatory authorities will be allowed to conduct site 
visits to the investigational facilities for the purpose of monitoring or inspecting any aspect of the 
clinical trial. The Investigator agrees to allow the Sponsor, their designee(s), the IRB, or 
regulatory authorities to inspect the study intervention storage area, study intervention stocks, 
study intervention records, participant charts and study source documents, and other records 
relative to study conduct. 

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Authorized representatives of the Sponsor, a regulatory authority, and the IRB may visit the site 
to perform audits or inspections, including source data verification. The purpose of a Sponsor 
audit or inspection is to systematically and independently examine all study-related activities and 
documents to determine whether these activities were conducted, and data were recorded, 
analyzed, and accurately reported according to the protocol, ICH GCP (R2), and any applicable 
regulatory requirements. The Investigator should contact the Sponsor immediately if contacted 
by a regulatory agency about an inspection. 
The Principal Investigator must obtain IRB approval for the investigation. Initial IRB approval 
and all materials approved by the IRB for this clinical trial, including the participant consent 
form and recruitment materials, must be maintained by the Investigator and made available for 
inspection. 
10.1.3. 
Financial Disclosure  
The Investigator is required to provide financial disclosure information to allow the Sponsor to 
submit the complete and accurate certification or disclosure statements required under 21 CFR 54. 
In addition, the Investigator must provide the Sponsor with a commitment to promptly update 
this information if any relevant changes occur during the course of the investigation and for 
1 year following the completion of the clinical trial. 
The Sponsor, the CRO, and the study site are not financially responsible for further testing or 
treatment of any medical condition that may be detected during the Screening process. In 
addition, in the absence of specific arrangements, the Sponsor, the CRO, and the study site are 
not financially responsible for further treatment of the disease under study. 
10.1.4. 
Informed Consent Process  
The ICF(s) must meet the requirements of 21 CFR 50, local regulations, ICH guidelines, HIPAA 
requirements, where applicable, and the IRB/IEC or study center. All consent documents will be 
approved by the appropriate IRB/IEC. The actual ICF used at each center may differ, depending 
on local regulations and IRB/IEC requirements. However, all versions must contain the standard 
information found in the sample ICF provided by the Sponsor. Any change to the content of the 
ICF must be approved by the Sponsor and the IRB/IEC prior to the form being used. 
If new information becomes available that may be relevant to the participant’s willingness to 
continue participation in the clinical trial, this will be communicated to the participant in a timely 
manner. Such information will be provided via a revised ICF or an addendum to the original ICF. 
The Investigator or his/her/their representative will explain the nature of the clinical trial to the 
participant and answer all questions regarding the clinical trial. 
The Investigator is responsible for ensuring that the participant fully understands the nature and 
purpose of the clinical trial. Information should be given in both oral and written form whenever 
possible. 
No participant should be obliged to participate in the clinical trial. The participant must be 
informed that participation is voluntary. Participants, their relatives, guardians, or (if applicable) 
legal representatives must be given ample opportunity to inquire about details of the clinical trial. 
The information must make clear that refusal to participate in the clinical trial or withdrawal 
from the clinical trial at any stage is without any prejudice to the participant’s subsequent care. 

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The participant must be allowed sufficient time to decide whether they wish to participate. 
The participant must be made aware of and give consent to direct access to his/her/their source 
medical records by study monitors, auditors, the IRB/IEC, and regulatory authorities. The 
participant should be informed that such access will not violate participant confidentiality or any 
applicable regulations. The participant should also be informed that they are authorizing such 
access by signing the ICF. 
A copy of the ICF(s) must be provided to the participant. 
A participant who is rescreened is not required to sign another ICF if the re-Screening occurs 
within 28 days from the previous ICF signature date. 
The ICF will contain a separate section/consent form(s) that addresses the use of remaining 
mandatory samples for optional exploratory research. The Investigator or authorized designee 
will explain to each participant the objectives of the exploratory research. A participant will be 
told that they are free to refuse participation and may withdraw their consent at any time and for 
any reason during the storage period. A separate signature will be required to document 
agreement to allow any remaining specimens to be used for exploratory research. A participant 
who declines to participate in this optional research will not provide this separate signature. 
10.1.5. 
Protocol Amendments  
No change or amendment to this protocol may be made by the Investigator or the Sponsor after 
the protocol has been agreed to and signed by all parties unless such change(s) or amendment(s) 
has (have) been agreed upon by the Investigator or the Sponsor. Any change agreed upon will be 
recorded in writing, and the written amendment will be signed by the Investigator and the 
Sponsor. Institutional review board approval is required prior to the implementation of an 
amendment, unless overriding safety reasons warrant immediate action, in which case, the 
IRB(s)/IEC(s) will be promptly notified. 
Any modifications to the protocol or the ICF, which may affect the conduct of the clinical trial, 
potential benefit of the clinical trial, or may affect participant safety, including changes of study 
objectives, study design, participant population, sample sizes, study procedures, or significant 
administrative aspects will require a formal amendment to the protocol. Such amendment will be 
released by the Sponsor, agreed by the Investigator(s), and approved by the relevant 
IRB(s)/IEC(s) prior to implementation. A signed and dated statement that the protocol, any 
subsequent relevant amended documents, and the ICF have been approved by relevant 
IRB(s)/IEC(s) must be provided to the Sponsor before the clinical trial is initiated. 
Administrative changes of the protocol are minor corrections and/or clarifications that have no 
effect on the way the clinical trial is to be conducted. These administrative changes will be 
released by the Sponsor, agreed by the Investigator(s), and notified to the IRB(s)/IEC(s). 
10.1.6. 
Protocol Deviations  
The noncompliance may be either on the part of the participant, the Investigator, or the study site 
staff (or delegate). As a result of deviations, corrective actions are to be developed by the site 
and implemented promptly. 

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It is the responsibility of the site Investigator to use continuous vigilance to identify and report 
deviations to the Sponsor or its designee. All deviations must be addressed in study source 
documents and reported to the study monitor. Protocol deviations must be sent to the reviewing 
IRB/IEC per their policies. The site Investigator is responsible for knowing and adhering to the 
reviewing IRB/IEC requirements. 
10.1.7. 
Recruitment Strategy  
Enrollment targets will be established to ensure the participant population reflects those that are 
most at risk for the condition, or those that are most reflective of the general population, if 
appropriate. 
Participant recruitment and retention initiatives will be incorporated into the trial. These include, 
but are not limited to, services that provide a means to identify potential participants and direct 
them to participating clinical trial sites, participant support services such as concierge, trial 
information, and support collateral for both the participant and the site. Advertisements to be 
used for the recruitment of study participants, and any other written information regarding 
this study to be provided to the participant should be submitted to the Sponsor for approval. All 
documents must be approved by the IRB/IEC. 
10.1.8. 
Data Protection  
Participants will be assigned a unique identifier by the Sponsor. Any participant records or 
datasets that are transferred to the Sponsor will contain the identifier only; participant names or 
any information which would make the participant identifiable will not be transferred. 
The participant must be informed that their personal study-related data will be used by the 
Sponsor in accordance with local data protection law. The level of disclosure must also be 
explained to the participant. 
The participant must be informed that their medical records may be examined by Clinical 
Quality Assurance auditors or other authorized personnel appointed by the Sponsor, by 
appropriate IRB/IEC members, and by inspectors from regulatory authorities. 
Individual participant medical information obtained as a result of this clinical trial is considered 
confidential, and disclosure to third parties is prohibited. Information will be accessible to 
authorized parties or personnel only. Medical information may be given to the participant’s 
physician or to other appropriate medical personnel responsible for the participant’s well-being. 
Each participant will be asked to complete a form allowing the Investigator to notify the 
participant’s primary health care provider of their participation in this clinical trial. 
All laboratory specimens, evaluation forms, reports, and other records will be identified in a 
manner designed to maintain participant confidentiality. All records will be kept in a secure 
storage area with limited access. Clinical information will not be released without the written 
permission of the participant, except as necessary for monitoring and auditing by the Sponsor, its 
designee, the relevant regulatory authority, or the IRB/IEC. 
The Investigator and all employees and coworkers involved with this clinical trial may not 
disclose or use for any purpose other than performance of the clinical trial, any data, record, or 
other unpublished, confidential information disclosed to those individuals for the purpose of the 

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clinical trial. Prior written agreement from the Sponsor or its designee must be obtained for the 
disclosure of any confidential information to other parties. 
10.1.9. 
Sample Retention and Future Biomedical Research  
The Sponsor may store samples for the time frame specified in the ICF to achieve study 
objectives. In addition, identifiable samples can be destroyed at any time at the request of the 
participant. During the clinical trial, or during the retention period, in addition to the analysis 
outlined in the study endpoints, exploratory analysis may be conducted using other measures of 
adaptive immunity and include humoral and cellular immune assay methodologies to measure 
responses to influenza and/or SARS-CoV-2 on any remaining blood or serum samples, including 
samples from participants who are screened but are not subsequently enrolled. These analyses 
will extend the search for other potentially relevant biomarkers to investigate the effect of 
mRNA-1083 as well as to determine how changes in biomarkers may relate to exposure to 
mRNA vaccines and clinical outcomes. A decision to perform such exploratory research may 
arise from new scientific findings related to the drug class or disease, as well as reagent and 
assay availability. 
10.1.10. 
Dissemination of Clinical Study Data  
The Sponsor shares information about clinical trials and results on publicly accessible websites, 
based on international and local legal and regulatory requirements, and other clinical trial 
disclosure commitments established by pharmaceutical industry associations. These websites 
include, but are not limited to, clinicaltrials.gov and clinicaltrialsregister.eu (EU.CTR), as well as 
other national registries. 
10.1.11. 
Data Quality Assurance  
Data collection is the responsibility of the clinical study staff (or delegate) at the site under the 
supervision of the site Investigator. The Investigator is responsible for ensuring the accuracy, 
completeness, legibility, and timeliness of the data reported. 
• All participant data relating to the study will be recorded in the eCRF unless 
transmitted to the Sponsor or designee electronically (eg, laboratory data). The 
Investigator is responsible for verifying that data entries are accurate and correct by 
physically or electronically signing the eCRF. 
• The Investigator must maintain accurate documentation (source data) that supports 
the information entered in the eCRF. 
• The Investigator must permit study-related monitoring, audits, IRB/IEC review, 
regulatory agency inspections, and provide direct access to source data documents. 
• Monitoring details describing strategy (eg, risk-based initiatives in operations and 
quality such as Risk Management and Mitigation Strategies and Analytical 
Risk-Based Monitoring); methods; responsibilities; and requirements, including 
handling of noncompliance issues and monitoring techniques (central, remote, or 
onsite monitoring) are provided in the Clinical Monitoring Plan. 
• The Sponsor or designee is responsible for the data management of this clinical trial 
including quality checking of the data. 

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• The Sponsor assumes accountability for actions delegated to other individuals 
(eg, CROs). 
• Study monitors will perform ongoing source data verification to confirm that data 
entered into the eCRF by authorized site personnel are accurate, complete, and 
verifiable from source documents; that the safety and rights of participants are being 
protected; and that the clinical trial is being conducted in accordance with the 
currently approved protocol and any other study agreements, ICH GCP, and all 
applicable regulatory requirements. 
• Records and documents, including signed ICFs, pertaining to the conduct of this 
clinical trial must be retained by the Investigator for a period of at least 2 years after 
the last marketing application approval or, if not approved, 2 years following the 
discontinuance of the test article for investigation. If this requirement differs from any 
local regulations, the local regulations will take precedence unless the local retention 
policy is less than 2 years. No records may be destroyed during the retention period 
without the written approval of the Sponsor. No records may be transferred to another 
location or party without written notification to the Sponsor. 
Quality assurance includes all the planned and systematic actions that are established to ensure 
that the clinical trial is performed and the data are generated, documented (recorded), and 
reported according to ICH GCP and local/regional regulatory standards. 
A quality assurance representative from Sponsor or qualified designee, who is independent of 
and separated from routine monitoring, may periodically arrange inspections/audits of the 
clinical trial by reviewing the data obtained and procedural aspects. These inspections may 
include onsite inspections/audits and source data checks. Direct access to source documents is 
required for the purpose of these periodic inspections/audits. 
10.1.12. 
Data Collection and Management  
This clinical trial will be conducted in compliance with ICH CGP guidelines. This clinical trial 
will also be conducted in accordance with the most recent version of the Declaration of Helsinki. 
This clinical trial will use electronic data collection to collect data directly from the 
investigational site using eCRFs. The Investigator is responsible for ensuring that all sections of 
each eCRF are completed promptly and correctly and that entries can be verified against any 
source data. 
Study monitors will perform source document verification to identify inconsistencies between 
the eCRFs and source documents. Discrepancies will be resolved in accordance with the 
principles of GCP. Detailed study monitoring procedures are provided in the Clinical Monitoring 
Plan. 
Adverse events will be coded with MedDRA. Concomitant medications will be coded using 
WHO - Drug Reference List. 
10.1.13. 
Source Documents  
Source documents are original documents or certified copies, and include, but are not limited to, 
eDiaries, medical, and hospital records, Screening logs, ICFs, telephone contact logs, and 

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worksheets. Source documents provide evidence for the existence of the participant and 
substantiate the integrity of the data collected. Source documents are filed at the Investigator’s 
site. 
Data reported on the CRF or entered in the eCRF that are transcribed from source documents 
must be consistent with the source documents or the discrepancies must be explained. The 
Investigator may need to request previous medical records or transfer records, depending on the 
clinical trial. Also, current medical records must be available. 
The Sponsor or its designee requires that the Investigator prepare and maintain adequate and 
accurate records for each participant treated with the study intervention. Source documents such 
as any hospital, clinic, or office charts, and the signed ICFs are to be included in the 
Investigator’s files with the participant’s study records. 
10.1.14. 
Study and Site Start and Closure  
If the clinical trial is prematurely terminated or suspended, the Sponsor shall promptly inform the 
Investigators, the IRBs/IECs, the regulatory authorities, and any CRO(s) used in the clinical trial 
of the reason for termination or suspension, as specified by the applicable regulatory 
requirements. The Investigator shall promptly inform the participant and should assure 
appropriate participant therapy and/or follow-up. 
The Sponsor or designee reserves the right to close the study site or terminate the clinical trial at 
any time for any reason at the sole discretion of the Sponsor. 
The Investigator may initiate study site closure at any time, provided there is reasonable cause 
and sufficient notice is given in advance of the intended termination. 
Reasons for the early closure of a study site by the Sponsor or Investigator may include but are 
not limited to: 
• Continuation of the clinical trial represents a significant medical risk to participants. 
• Failure of the Investigator to comply with the protocol, the requirements of the 
IRB/IEC or local health authorities, the Sponsor's procedures, or GCP guidelines. 
• Inadequate recruitment of participants by the Investigator. 
Study sites will be closed upon study completion. A study site is considered closed when all 
required documents and study supplies have been collected and a study site closure visit has been 
performed. 
10.1.15. 
Publication Policy  
The results of this clinical trial may be published or presented at scientific meetings. If this is 
foreseen, the Investigator agrees to submit all manuscripts or abstracts to the Sponsor before 
submission. This allows the Sponsor to protect proprietary information and to provide comments. 
The Sponsor will comply with the requirements for publication of study results. In accordance 
with standard editorial and ethical practice, the Sponsor will generally support publication of 
multicenter studies only in their entirety and not as individual site data. In this case, a 
coordinating Investigator will be designated by mutual agreement. 

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Authorship will be determined by mutual agreement and in line with International Committee of 
Medical Journal Editors authorship requirements. 
The clinical study plan and the results of the clinical trial will be published on 
www.ClinicalTrials.gov in accordance with 21 CFR 50.25(c). The results of and data from this 
study belong to the Sponsor. 
 
 

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10.2. 
Appendix 2: Clinical Laboratory Tests  
The tests detailed in Table 12 will be performed by the central laboratory. 
Protocol-specific requirements for inclusion or exclusion of participants are detailed in Section 5 
of the protocol. 
Additional tests may be performed at any time during the clinical trial as determined necessary 
by the Investigator or required by local regulations. If a local sample is clinically indicated, it is 
important that the sample for central analysis is obtained at the same time. Additionally, if the 
local laboratory results are used to make either a study intervention decision or response 
evaluation, the results must be recorded. 
Investigators must document their review of each laboratory safety report. 
Table 12: 
Protocol-required Safety Laboratory Tests (Part 1)  
Laboratory Tests 
Parameters 
Hematology 
• 
White blood cell (WBC) count 
• 
Platelet count 
• 
Hematocrit 
• 
Hemoglobin 
Clinical Chemistrya 
• 
Creatinine 
• 
Aspartate aminotransferase (AST) 
• 
Alanine aminotransferase (ALT) 
• 
Alkaline phosphataseb 
• 
Total bilirubin 
Pregnancy Testing 
• 
Highly sensitive [serum or urine] human chorionic gonadotropin (hCG) 
pregnancy test (as needed for participants of childbearing potential)c 
Other Screening Tests 
• 
Follicle-stimulating hormone (FSH) and estradiol (as needed in 
participants of nonchildbearing potential only)d 
a. 
All events of ALT [or AST] ≥3 × upper limit of normal (ULN) and total bilirubin ≥2 × ULN or ALT [or AST] 
≥3 × ULN must be reported to Sponsor in an expedited manner. 
b. 
If alkaline phosphatase is elevated, consider fractionating. 
c. 
Local urine testing will be standard for the protocol unless serum testing is required by local regulation or 
IRB/IEC. 
d. 
For participants assigned female at birth and of nonchildbearing potential, the FSH level may be measured at 
the Screening Visit, as necessary, and at the discretion of the Investigator, to confirm menopausal status. 

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10.3. 
Appendix 3: AEs and SAEs: Definitions and Procedures for 
Recording, Evaluating, Follow-up, and Reporting  
10.3.1. 
Definition of AE  
AE Definition 
An AE is defined as any untoward medical occurrence associated with the use of a drug/vaccine 
in humans, whether or not considered related to the drug/vaccine. 
Events Meeting the Adverse Event Definition 
Exacerbation of a chronic or intermittent pre-existing condition including an increase in 
frequency and/or intensity of the condition, after the study intervention. 
• New conditions detected or diagnosed after the study intervention even though they 
may have been present before the start of the clinical trial. 
Events NOT Meeting the Adverse Event Definition 
• Procedures planned before study entry (eg, hospitalization for preplanned surgical 
procedure). 
• Medical or surgical procedure (eg, endoscopy, appendectomy): the condition that 
leads to the procedure should be the AE. 
• Situations in which an untoward medical occurrence did not occur (social and/or 
convenience admission to a hospital). 
An unsolicited AE (Section 10.3.4) is any AE reported by the participant that is not specified as a 
solicited AR in the protocol or is specified as a solicited AR in the protocol but starts outside the 
protocol-defined period for reporting solicited ARs (ie, for the 7 days after vaccination). 
10.3.2. 
Definition of Serious Adverse Events  
An AE (including an AR) is considered an SAE if, in the view of either the Investigator or 
Sponsor, it results in any of the following outcomes: 
• Results in death 
A death that occurs during the clinical trial or that comes to the attention of the 
Investigator during the protocol-defined follow-up period must be reported to the 
Sponsor, whether or not it is considered related to study intervention. 
• Is life-threatening 
An AE is considered life-threatening if, in the view of either the Investigator or the 
Sponsor, its occurrence places the participant at immediate risk of death. It does not 
include an AE that, had it occurred in a more severe form, might have caused death. 
• Inpatient hospitalization or prolongation of existing hospitalization 
In general, inpatient hospitalization indicates the participant was admitted to the 
hospital or emergency ward for at least 1 overnight stay for observation and/or 
treatment that would not have been appropriate in the physician’s office or outpatient 
setting. The hospital or emergency ward admission should be considered an SAE 

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regardless of whether opinions differ as to the necessity of the admission. 
Complications that occur during inpatient hospitalization will be recorded as AEs; 
however, if a complication/AE prolongs hospitalization or otherwise fulfills SAE 
criteria, the complication/AE will be recorded as a separate SAE. Procedures planned 
before study entry (eg, hospitalization for preplanned surgical procedure) are not 
considered SAEs. 
• Persistent or significant incapacity or substantial disruption of the ability to 
conduct normal life functions 
This definition is not intended to include experiences of relatively minor medical 
significance such as uncomplicated headache, nausea/vomiting, diarrhea, influenza, 
and accidental trauma (eg, sprained ankle) which may interfere with or prevent 
everyday life functions but do not constitute a substantial disruption. 
• Congenital anomaly or birth defect. 
• Medically important event 
Medical judgment should be exercised in deciding whether SAE reporting is 
appropriate in other situations, such as important medical events that may not be 
immediately life-threatening or result in death or hospitalization but may jeopardize 
the participant or require medical or surgical intervention to prevent one of the other 
outcomes listed in the above definition. These events should usually be considered 
serious. Examples of such medical events include allergic bronchospasm requiring 
intensive treatment in an emergency room or at home, blood dyscrasias or 
convulsions that do not result in inpatient hospitalization, or the development of drug 
dependency or drug abuse. 
10.3.3. 
Solicited Adverse Reactions  
Solicited ARs are predefined local (at the injection site) and systemic events/symptoms that 
participants are specifically asked, and which are noted by the participant in their eDiary. 
The solicited ARs for this clinical trial include selected signs and symptoms that are typically 
associated with vaccine reactogenicity. Reactogenicity refers to the occurrence and intensity of 
local and systemic ARs commonly following vaccination. The eDiary will solicit daily 
participant reporting of ARs using a structured checklist (Section 8.3.10). Participants will record 
such occurrences in an eDiary on the day of vaccination and for the 6 days after the day of 
dosing. 
Severity grading of reactogenicity will occur automatically based on participant entry into the 
eDiary according to the grading scales presented in Table 13 modified from the Toxicity grading 
scale for healthy adult and adolescent volunteers enrolled in preventive vaccine clinical trials 
(DHHS 2007). All solicited ARs (local and systemic) will be considered causally related to 
dosing. 
Study sites will distribute Sponsor-provided oral thermometers and rulers for use by participants 
to assess body temperature and injection site reactions, respectively, for recording solicited ARs 
in the eDiaries. Based on availability, smartphone devices may be provided to those participants 
who do not have their own device to use for eDiary activities. 

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Table 13: 
Solicited Adverse Reactions and Grades  
Reaction 
Grade 0 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Injection site pain 
None 
Does not 
interfere with 
activity 
Interferes with 
activity 
Prevents daily 
activity 
Requires 
emergency 
room visit or 
hospitalization 
Injection site 
erythema (redness) 
<25 mm/ 
<2.5 cm 
25 to 50 mm/ 
2.5 to 5 cm 
51 to 100 mm/ 
5.1 to 10 cm 
>100 mm/ 
>10 cm 
Necrosis or 
exfoliative 
dermatitis 
Injection site 
swelling/ 
induration 
(hardness) 
<25 mm/ 
<2.5 cm 
25 to 50 mm/ 
2.5 to 5 cm 
51 to 100 mm/ 
5.1 to 10 cm 
>100 mm/ 
>10 cm 
Necrosis 
Axillary 
(underarm) 
swelling or 
tenderness 
ipsilateral to the 
side of injection 
None 
No interference 
with activity 
Some 
interference 
with activity 
Prevents daily 
activity 
Emergency 
room visit or 
hospitalization 
Headache 
None 
No interference 
with activity 
Some 
interference 
with activity 
Prevents daily 
activity 
Requires 
emergency 
room visit or 
hospitalization 
Fatigue 
None 
No interference 
with activity 
Some 
interference 
with activity 
Prevents daily 
activity 
Requires 
emergency 
room visit or 
hospitalization 
Myalgia (muscle 
aches all over 
body) 
None 
No interference 
with activity 
Some 
interference 
with activity 
Prevents daily 
activity 
Requires 
emergency 
room visit or 
hospitalization 
Arthralgia (joint 
aches in several 
joints) 
None 
No interference 
with activity 
Some 
interference 
with activity 
Prevents daily 
activity 
Requires 
emergency 
room visit or 
hospitalization 
Nausea/vomiting 
None 
No interference 
with activity or 
1 to 2 episodes/ 
24 hours 
Some 
interference 
with activity or 
>2 episodes/ 
24 hours 
Prevents daily 
activity, 
requires 
outpatient 
intravenous 
hydration 
Requires 
emergency 
room visit or 
hospitalization 
for hypotensive 
shock 

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Reaction 
Grade 0 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Chills 
None 
No interference 
with activity 
Some 
interference 
with activity 
not requiring 
medical 
intervention 
Prevents daily 
activity and 
requires 
medical 
intervention 
Requires 
emergency 
room visit or 
hospitalization 
Fever (oral) 
<38.0°C 
<100.4°F 
38.0 to 38.4°C 
100.4 to 
101.1°F 
38.5 to 38.9°C 
101.2 to 
102.0°F 
39.0 to 40.0°C 
102.1 to 
104.0°F 
>40.0°C 
>104.0°F 
Note: Events listed above but starting >7 days post study intervention administration will be recorded on the AE 
page of the electronic case report form (eCRF). Causality for each event will be determined per assessment by the 
Investigator. 
Any solicited AR that meets any of the following criteria must be entered into the participant’s 
source document and must also be recorded in the participant’s Reactogenicity eCRF: 
• Solicited local or systemic AR that results in a visit to an HCP (MAAE; 
Section 10.3.4) 
• Solicited local or systemic AR leading to the participant withdrawing from the 
clinical trial or the participant being withdrawn from the clinical trial by the 
Investigator (AE leading to withdrawal) 
• Solicited local or systemic AR lasting beyond 7 days post-injection 
• Solicited local or systemic AR that otherwise meets the definition of an SAE 
Additionally: 
• If a participant reported a solicited AR during the solicited period and did not record 
the event in the eDiary, the event should be recorded on the Reactogenicity page of 
the eCRF. 
• If the event starts during the solicited period, but continues beyond 7 days after 
dosing, the participant should notify the site to provide an end date to close out the 
event on the Reactogenicity page of the eCRF. 
• If the participant reported an event after the solicited period (ie, after Day 7), it should 
be recorded as an AE on the AE page of the eCRF. 
10.3.4. 
Definition of Unsolicited Adverse Events  
An unsolicited AE is an AE that was not solicited using a participant eDiary and that is 
communicated by a participant who has signed the informed consent. Unsolicited AEs include 
serious and nonserious AEs. 
• Potential unsolicited AEs may be medically attended (ie, symptoms or illnesses 
requiring a hospitalization, emergency room visit, or visit to/by a healthcare 
provider). The participants will be instructed to contact the site as soon as possible to 
report medically attended event(s), as well as any events that, though not medically 

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attended, are of participant concern. Detailed information about reported unsolicited 
AEs will be collected by qualified site personnel and documented in the participant’s 
records. 
• Unsolicited AEs that are not medically attended nor perceived as a concern by the 
participant will be collected during an interview with the participants and by review 
of available medical records at the next visit. 
10.3.5. 
Medically Attended Adverse Events  
An MAAE is an AE that leads to an unscheduled visit to an HCP. This would include visits to a 
study site for unscheduled assessments (eg, rash assessment, abnormal laboratory follow-up, 
COVID-19 [Section 10.3.8]) and visits to HCPs external to the study site (eg, urgent care, 
primary care physician). Investigators will review unsolicited AEs for the occurrence of any 
MAAEs. An unscheduled visit for assessment of protocol-defined ILI is not considered an 
MAAE unless additional medical evaluation, including examinations/testing not required PP 
and/or treatment is provided during the visit. All MAAEs will be collected through the entire 
study period. 
10.3.6. 
Adverse Events of Special Interest  
An AESI is an AE (serious or nonserious) of scientific and medical concern specific to the 
Sponsor’s product or program for which ongoing monitoring and immediate notification by the 
Investigator to the Sponsor is required and documentation is in the form of a case narrative. Such 
events may require further investigation to characterize and understand them. 
Section 10.4 (Appendix 4) provides a list of AESIs pertinent to this clinical trial. 
All AESIs will be collected through the entire study period and must be reported to the Sponsor 
or designee immediately and in all circumstances within 24 hours of becoming aware of the 
event via the EDC. If a site receives a report of a new AESI from a study participant or receives 
updated data on a previously reported AESI at a time after the eCRF has been taken offline, then 
the site can report this information on a paper SAE/AESI form using the SAE Mailbox, or the 
SAE Fax line (Section 10.3.10). 
10.3.6.1. Anaphylaxis  
All suspected cases of anaphylaxis associated with study intervention administration should be 
recorded as an SAE, based on the criteria for a medically important event, unless the event meets 
other serious criteria. As an SAE, the event should be reported to the Sponsor or designee 
immediately and in all circumstances within 24 hours per Section 10.3.10. The Investigator will 
submit any updated anaphylaxis case data to the Sponsor within 24 hours of it being available. 
For reporting purposes, a participant who displays signs or symptoms consistent with 
anaphylaxis (as described below) should be reported as a potential case of anaphylaxis. This is 
provided as general guidance for Investigators and is based on the Brighton Collaboration case 
definition (Rüggeberg et al 2007). 
Anaphylaxis is an acute hypersensitivity reaction with multi-organ system involvement that can 
present as, or rapidly progress to, a severe life-threatening reaction. It may occur following 
exposure to allergens from a variety of sources. 

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• Anaphylaxis is a clinical syndrome characterized by the following: 
• Sudden onset AND 
• Rapid progression of signs and symptoms AND 
• Involves 2 or more organ systems, as follows: 
Skin/mucosal: urticaria (hives), generalized erythema, angioedema, generalized pruritus with 
skin rash, generalized prickle sensation, and red and itchy eyes. 
Cardiovascular: measured hypotension, clinical diagnosis of uncompensated shock, loss of 
consciousness or decreased level of consciousness, and evidence of reduced peripheral 
circulation. 
Respiratory: bilateral wheeze (bronchospasm), difficulty breathing, stridor, upper airway 
swelling (lip, tongue, throat, uvula, or larynx), respiratory distress, persistent dry cough, hoarse 
voice, sensation of throat closure, sneezing, and rhinorrhea. 
Gastrointestinal: diarrhea, abdominal pain, nausea, and vomiting. 
10.3.6.2. Myocarditis/Pericarditis/Myopericarditis  
Any case that has either a high clinical index of suspicion for myocarditis or pericarditis, or 
which is considered to be a confirmed case of myocarditis, pericarditis, or myopericarditis, 
should be reported as an AESI. The event should also be reported as an SAE if it meets 
seriousness criteria (see Section 10.3.2). The CDC has developed a working case definition for 
myocarditis, pericarditis, and myopericarditis, which is provided to inform the evaluation of 
suspected cases (see Section 10.3.6.2). The CDC document is intended for guidance only; the 
Investigator is expected to apply medical judgment in the evaluation of suspected cases, which 
may be prompted by a participant reporting symptoms concerning for myocarditis and/or 
pericarditis (per the CDC case definition). 
Similarly, the diagnostic work up (eg, ECG, echocardiogram) and laboratory testing (eg, 
troponin) outlined in the CDC definition should be considered as a guidance to the Investigator, 
and promptly obtained if considered clinically indicated in any participant with concerning 
signs/symptoms. Referral to a cardiologist should be considered in those with positive tests 
results or clinically significant symptoms without other identifiable causes. The Investigator 
must submit any updated myocarditis, pericarditis or myopericarditis case data to the Sponsor 
within 24 hours of it being available. Cases of myocarditis and pericarditis will be followed until 
resolution of symptoms and abnormal test findings. Participants with events of myocarditis 
and/or pericarditis should continue to be followed in the clinical trial for safety as per the 
protocol assuming consent is not withdrawn. 
In the event that a case is evaluated for myocarditis, pericarditis, or myopericarditis, and the 
Investigator considers that the findings do not support the diagnosis of myocarditis, pericarditis, 
or myopericarditis, the case should not be reported as an AESI. 
An independent Cardiac Event Adjudication Committee (CEAC) that includes cardiologists will 
review suspected cases of myocarditis and pericarditis to determine if they meet CDC criteria of 
“probable” or “confirmed” events and make recommendations to the Sponsor. 
(Gargano et al 2021). The CEAC operates under the rules of an approved charter. Details 

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regarding the CEAC composition, responsibilities, procedures, and frequency of data review is 
defined in its charter. 
The CDC case definition is provided in Section 10.7 (Appendix 7) as guidance. 
10.3.7. 
Influenza-Like Illness  
A protocol-defined ILI is determined by the occurrence of at least 1 respiratory illness symptom 
concurrently with at least 1 systemic symptom or the occurrence of any 2 or more respiratory 
symptoms as defined below. 
Respiratory Symptoms 
Systemic Symptoms 
Sore throat 
Cough/rhinorrhea/nasal congestion (≥1 of the 
3 symptoms count as 1 respiratory symptom) 
Sputum production 
Wheezing 
Difficulty breathing 
Body temperature >37.2°C (>99°F) 
Chills 
Tiredness 
Headache 
Myalgia 
Nausea/Vomiting 
Diarrhea 
A CDC-defined ILI is defined as body temperature ≥37.8°C (100°F) accompanied by a cough 
and/or sore throat. 
An RT-PCR-confirmed ILI is defined as a positive influenza result by RT-PCR done at any 
setting during the study period. 
10.3.8. 
Suspicion of SARS-CoV-2 Infection  
SARS-CoV-2 should be suspected if the participant experiences any one of the symptoms listed 
below lasting at least 48 hours (except for fever and/or respiratory symptoms) (CDC 2020b): 
• Fever (temperature ≥38.0°C [100.4°F]) or chills (of any duration, including 
≤48 hours) 
• Cough (of any duration, including ≤48 hours) 
• Shortness of breath and/or difficulty breathing (of any duration, including ≤48 hours) 
• Fatigue 
• Muscle or body aches 
• Headache 
• New loss of taste and/or smell 
• Sore throat, congestion, or runny nose 
• Nausea or vomiting 
• Diarrhea 
Symptomatic COVID-19 is defined by the presence of one of the CDC-listed symptoms 
(CDC 2020c) and a positive RT-PCR test on a respiratory sample. Asymptomatic SARS-CoV-2 

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infection is defined as a positive RT-PCR test on a respiratory sample in the absence of 
symptoms or a positive serologic test for antinucleocapsid antibody after a negative test result at 
the time of enrollment, with the serologic assay detecting previously resolved SARS-CoV-2 
infections that may have occurred between visits, and the RT-PCR to detect active viral infection 
at the time of a visit. If participants are confirmed to have SARS-CoV-2 infection and are 
symptomatic or asymptomatic, the Investigator will notify the participants’ primary care 
physicians of the diagnosis and the local public health authorities as required per local 
regulations. 
If the participant had known exposure to COVID-19 (eg, exposure to someone with a confirmed 
case of COVID-19), it will be captured in the COVID-19 exposure form, and the participant will 
continue to follow all remaining study assessments as scheduled. Likewise, participants with a 
confirmed case of COVID-19 will continue to follow all remaining study assessments as 
scheduled. 
10.3.9. 
Recording and Follow-Up of AE and/or SAE  
The Investigator and any qualified designees are responsible for detecting, documenting, and 
recording events that meet the definition of an AE, including SAEs, and remain responsible for 
following up AEs until resolution, stabilization, the event is otherwise explained, or the 
participant is LTFU, as defined in Section 7.3. 
All unsolicited AEs reported or observed during the clinical trial will be recorded on the AE page 
of the eCRF. All unsolicited AEs will be collected from start of study intervention through 
28 days after injection. 
All SAEs reported or observed during the clinical trial will be recorded on the SAE page of the 
eCRF. All SAEs will be collected from the start of study intervention until EoS visit at the 
timepoints specified in the SoA (Table 1). 
Information to be collected includes type of event, time of onset, Investigator-specified 
assessment of severity and relationship to study intervention, time of resolution of the event, 
seriousness, as well as any required treatment or evaluations, and outcome. The unsolicited AEs 
resulting from concurrent illnesses, reactions to concurrent illnesses, reactions to concurrent 
medications, or progression of disease states must also be reported. All AEs will be followed 
until they are resolved or stable or judged by the Investigator to be not clinically significant. The 
MedDRA will be used to code all unsolicited AEs. 
After the initial AE/SAE report, the Investigator is required to proactively follow each 
participant at subsequent visits/contacts. All AEs, SAEs, and AEs of special interest (as defined 
in Section 10.3.6) will be followed until resolution, stabilization, the event is otherwise 
explained, or the participant is LTFU (as defined in Section 7.3). Further information on follow-
up procedures is provided in Section 10.3. 
10.3.9.1. Assessment of Intensity  
The severity (or intensity) of an AR or AE refers to the extent to which it affects the participant’s 
daily activities. The Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers 
Enrolled in Preventive Vaccine Clinical Trials (DHHS 2007) will be used to categorize local and 
systemic reactogenicity events (solicited ARs), clinical laboratory test results, and vital sign 

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measurements observed during this clinical trial. Specific criteria for local and systemic 
reactogenicity events are presented in Section 10.3.3. 
The determination of severity for all unsolicited AEs should be made by the Investigator based 
upon medical judgment and the definition of severity as follows: 
• Mild: These events do not interfere with the participant’s daily activities. 
• Moderate: These events cause some interference with the participant’s daily 
activities and require limited or no medical intervention. 
• Severe: These events prevent the participant’s daily activity and require intensive 
therapeutic intervention. 
Study staff (or delegate) should elicit from the participant, the impact of AEs on the participant’s 
activities of daily living to assess severity and should document it appropriately in the 
participant’s source documentation. Changes in the severity of an AE should be documented in 
the participant’s source documentation to allow an assessment of the duration of the event at 
each level of intensity to be performed. An AE characterized as intermittent requires 
documentation of onset and duration of each episode. An AE that fluctuates in severity during 
the course of the event is reported once in the eCRF at the highest severity observed. 
10.3.9.2. Assessment of Causality  
The Investigator will assess causality (ie, whether there is a reasonable possibility that the study 
intervention caused the event) for all AEs and SAEs. The relationship will be characterized using 
the following classification: 
• Not related: There is not a reasonable possibility of a relationship to the study 
intervention. Participant did not receive the study intervention, OR temporal sequence 
of the AE onset relative to administration of the study intervention is not reasonable, 
OR the AE is more likely explained by another cause than the study intervention. 
• Related: There is a reasonable possibility of a relationship to the study intervention. 
There is evidence of exposure to the study intervention. The temporal sequence of the 
AE onset relative to the administration of the study intervention is reasonable. The 
AE is more likely explained by the study intervention than by another cause. 
10.3.10. 
Reporting of SAEs  
Prompt notification by the Investigator to the Sponsor of an SAE is essential so that legal 
obligations and ethical responsibilities toward the safety of participants and the safety of a study 
intervention under clinical investigation are met. 
Any AE considered serious by the Investigator or that meets SAE criteria (Section 10.3.2) must 
be reported to the Sponsor immediately (within 24 hours of becoming aware of the SAE) via the 
EDC. The Investigator will assess whether there is a reasonable possibility that the study 
intervention caused the SAE. The Sponsor will be responsible for notifying the relevant 
regulatory authorities of any SAE as required per the applicable regulations. The Investigator is 
responsible for notifying the IRB/IEC directly. 

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If the eCRF is unavailable at the time of the SAE, the event should be reported using the 
provided study-specific paper SAE/AESI Reporting Form and sent via the email address or fax 
number on the form. 
Regulatory reporting requirements for SAEs are described in Section 8.4.4. 

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10.4. 
Appendix 4: Adverse Events of Special Interest  
The Investigator’s medical judgment must be applied to assess an event as an AESI, as most 
AESIs are based on medical concepts. 
Table 14 does not provide a comprehensive list of terms. The table describes events/medical 
concepts that are of interest in COVID-19 vaccine safety surveillance. Some are specific to 
vaccines; however, some are of interest due to their occurrence in the context of concurrent or 
recent COVID-19. Events falling into the descriptions below should be reported as AESIs, PP, 
even when they occur during/following COVID infection. 
Please note: COVID-19 itself is not an AESI. 
Table 14: 
Adverse Events of Special Interest  
Medical Concept 
Additional Notes 
Anosmia, Ageusia 
• 
New onset of anosmia or ageusia associated with 
COVID-19 or idiopathic etiology 
• 
DOES NOT INCLUDE anosmia or ageusia associated 
with sinus/nasal congestion, congenital, or traumatic 
etiologies  
Subacute thyroiditis 
• 
Acute inflammatory disease of the thyroid (immune-
mediated or idiopathic) 
• 
DOES NOT INCLUDE new onset of chronic thyroiditis 
Acute pancreatitis 
• 
New onset of pancreatitis in the absence of a clear, 
alternate etiology, such as alcohol, gallstones, trauma, 
recent invasive procedure, etc. 
Appendicitis 
• 
Any event of appendicitis  
Rhabdomyolysis 
• 
New onset of rhabdomyolysis in the absence of a clear, 
alternate etiology, such as drug/alcohol abuse, excessive 
exercise, trauma, etc. 
Acute respiratory distress syndrome 
(ARDS) 
• 
New onset of ARDS/respiratory failure due to acute 
inflammatory lung injury 
• 
DOES NOT INCLUDE nonspecific symptoms of 
shortness of breath or dyspnea, nor events with 
underlying etiologies of heart failure or fluid overload 
Coagulation disorders 
• 
New onset of thrombosis, thromboembolic event, or 
nontraumatic hemorrhage/bleeding disorder (eg, stroke, 
deep vein thrombosis [DVT], pulmonary embolism, 
disseminated intravascular coagulation [DIC], etc.) 

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Medical Concept 
Additional Notes 
Acute cardiovascular injury 
• 
New onset of clinically confirmed, acute cardiovascular 
injury, such as myocarditis, pericarditis, arrhythmia 
confirmed by electrocardiogram (eg, atrial fibrillation, 
atrial flutter, supraventricular tachycardia), stress 
cardiomyopathy, heart failure, acute coronary 
syndrome, myocardial infarction, etc. 
• 
DOES NOT INCLUDE transient sinus 
tachycardia/bradycardia, nonspecific symptoms such as 
palpitations, racing heart, heart fluttering or pounding, 
irregular heartbeats, shortness of breath, chest 
pain/discomfort, etc. 
Acute kidney injury 
• 
New onset of acute kidney injury or acute renal failure 
in the absence of a clear, alternate etiology, such as 
urinary tract infection/urosepsis, trauma, tumor, 
nephrotoxic medications/substances, etc; 
• 
Increase in serum creatinine by ≥0.3 mg/dL (or 
≥26.5 µmol/L) within 48 hours; 
OR 
• 
Increase in serum creatinine to ≥1.5 times Baseline, 
known or presumed to have occurred within prior 
7 days. 
Acute liver injury 
• 
New onset in the absence of a clear, alternate etiology, 
such as trauma, tumor, hepatotoxic 
medications/substances, etc: 
• 
>3-fold elevation above the upper normal limit for 
alanine aminotransferase or aspartate aminotransferase; 
OR 
• 
>2-fold elevation above the upper normal limit for total 
serum bilirubin or gamma-glutamyl transferase (GGT) 
or alkaline phosphatase 
Dermatologic findings 
• 
Chilblain-like lesions 
• 
Single organ cutaneous vasculitis 
• 
Erythema multiforme 
• 
Bullous rash 
• 
Severe cutaneous adverse reactions, such as Stevens-
Johnson syndrome, toxic epidermal necrolysis, drug 
reaction with eosinophilia and systemic symptoms 
(DRESS), fixed drug eruptions, and necrotic or 
exfoliative reactions 
Systemic inflammatory syndromes 
• 
Multisystem inflammatory syndrome in adults (MIS-A) 
or children (MIS-C) 
• 
Kawasaki’s disease 
• 
Hemophagocytic lymphohistiocytosis (HLH) 

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Medical Concept 
Additional Notes 
Thrombocytopenia 
• 
Platelet count <150 × 109/L 
• 
Including but not limited to immune thrombocytopenia, 
platelet production decreased, thrombocytopenia, 
thrombocytopenic purpura, thrombotic 
thrombocytopenic purpura, or hemolysis, elevated liver 
enzymes, and low platelets (HELLP) syndrome 
Acute aseptic arthritis 
• 
Clinical syndrome characterized by acute onset of signs 
and symptoms of joint inflammation without recent 
trauma for a period of no longer than 6 weeks, synovial 
increased leukocyte count and the absence of 
microorganisms on Gram stain, routine culture and/or 
polymerase chain reaction test. 
• 
DOES NOT INCLUDE new onset of chronic arthritic 
conditions. 
New onset, or worsening, of the 
following neurological diseases 
• 
Guillain-Barre Syndrome 
• 
Acute disseminated encephalomyelitis (ADEM) 
• 
Idiopathic peripheral facial nerve palsy (Bell’s palsy) 
• 
Seizures, including but not limited to febrile seizures 
and/or generalized seizures/convulsions 
Anaphylaxis 
• 
Anaphylaxis associated with study intervention 
administration as defined PP 
• 
Follow reporting procedures in protocol 
Section 10.3.6.1 
Myocarditis/Pericarditis 
• 
Myocarditis 
• 
Pericarditis 
• 
Myopericarditis 
Other syndromes 
• 
Fibromyalgia 
• 
Postural Orthostatic Tachycardia Syndrome 
• 
Chronic Fatigue Syndrome 
• 
Myalgic encephalomyelitis 
• 
Post viral fatigue syndrome 
• 
Myasthenia gravis 
10.5. 
Appendix 5: Safety Oversight and Committees Structure  
10.5.1. 
Internal Safety Team  
Safety monitoring for this clinical trial will include the blinded study team members, inclusive of 
at a minimum, the Sponsor’s medical monitor, a CRO medical monitor and an unblinded IST. 
The IST is comprised of the Sponsor’s physicians, who will not otherwise be involved in the 
conduct of the clinical trial. The study team will conduct ongoing blinded safety reviews during 
the clinical trial and will be responsible for notifying the IST of potential safety signal events or 
the triggering of pause rules. An unblinded statistician will support the determination if study 
pause rules have been met. 
For each Cohort, a scheduled IST safety review will occur after at least 10 participants/arm reach 
Day 8 (~120 in Cohort A and ~120 in Cohort B). The scheduled IST safety review for each 

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Cohort may be combined into 1 session for both Cohort A and B if the recruitment rate and the 
timing of the participants reaching Day 8 are close to each other. Enrollment will be ongoing 
while this review is conducted if no pause rules have been met and the study team has not 
identified any safety concerns. Additional ad hoc IST review may occur as outlined by the IST 
charter. 
In Part 2 of the study, there will be no scheduled IST review. An ad-hoc IST review may occur 
as outlined by the IST charter. 
10.5.2. 
Cardiac Event Adjudication Committee  
An independent CEAC that includes medically qualified personnel and cardiologists will review 
reported cases of myocarditis, pericarditis, and myopericarditis to determine if they meet CDC 
criteria of “probable” or “confirmed” events (Gargano et al 2021). Any cases that the CEAC 
assesses as representing “probable” or “confirmed” case of myocarditis, pericarditis, or 
myopericarditis will be referred to the Sponsor, who will then make a final decision on whether 
to suspend further enrollment and/or study treatment based on an assessment of the overall 
potential risk to study participants. 
The CEAC members will be blinded to study treatment. The CEAC will operate under the rules 
of an approved charter that will be written and reviewed at the organizational meeting of the 
CEAC. Details regarding the CEAC composition, responsibilities, procedures, and frequency of 
data review will be defined in its charter. 

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10.6. 
Appendix 6: Contraceptive and Barrier Guidance  
Definitions: 
Participant of Childbearing Potential 
1. Participants are considered participants of childbearing potential (POCBP) (fertile) 
from the time of menarche until becoming postmenopausal unless permanently sterile 
(see below). 
Participant of Non-Childbearing Potential 
1. A postmenopausal state is defined as no menses for 12 months without an alternative 
medical cause. 
• A high FSH level in the postmenopausal range may be used to confirm a 
postmenopausal state in participants not using hormonal contraception or hormonal 
replacement therapy (HRT). However, in the absence of 12 months of amenorrhea, 
confirmation with more than one FSH measurement is required. 
• Participants on HRT and whose menopausal status is in doubt will be required to use 
one of the nonestrogen hormonal highly effective contraception methods if they wish 
to continue their HRT during the clinical trial. Otherwise, they must discontinue HRT 
to allow confirmation of postmenopausal status before study enrollment. 
2. Permanent sterilization methods (for the purpose of this clinical trial) include: 
• Documented hysterectomy 
• Documented bilateral salpingectomy 
• Documented bilateral oophorectomy 
• Documented bilateral tubal ligation 
3. Permanent infertility due to an alternate medical cause other than the above, (eg, 
Mullerian agenesis, androgen insensitivity, gonadal dysgenesis), Investigator 
discretion should be applied to determining study entry. 
Note: Documentation can come from the site personnel’s review of the participant’s medical 
records, medical examination, or medical history interview. 
Note: If fertility is unclear (eg, amenorrhea in adolescents or athletes) and a menstrual cycle 
cannot be confirmed before first dose of study intervention, additional evaluation should be 
considered. 
Contraception Guidance: 
Highly effective contraception is defined as consistent and correct use of a contraceptive method 
in accordance with the product label. For example: 
• Barrier method (such as condoms, diaphragm, or cervical cap) with spermicide 
• Intrauterine device 
• Prescription hormonal contraceptive taken or administered via oral (pill), transdermal 
(patch), subdermal, or IM route 
• Sterilization of a participant’s monogamous partner prior to entry into the clinical trial 

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Note that periodic abstinence (eg, calendar, ovulation, symptothermal, postovulation methods) 
and withdrawal are not acceptable methods of contraception. 
CONTRACEPTIVESa ALLOWED DURING THE STUDY INCLUDE: 
Highly Effective Methodsb That Have Low User Dependency Failure rate of <1% per year when 
used consistently and correctly. 
• Implantable progestogen-only hormone contraception associated with inhibition of 
ovulationc 
• Intrauterine device (IUD) 
• Intrauterine hormone-releasing system (IUS)c 
• Bilateral tubal occlusion 
• Azoospermic partner (vasectomized or due to a medical cause) 
Azoospermia is a highly effective contraceptive method provided that the partner is the sole sexual 
partner of the participant of childbearing potential and the absence of sperm has been confirmed. 
If not, an additional highly effective method of contraception should be used. Spermatogenesis 
cycle is approximately 90 days. 
Note: documentation of azoospermia for a participant can come from the site personnel’s review of 
the participant’s medical records, medical examination, or medical history interview 
Highly Effective Methodsb That Are User Dependent Failure rate of <1% per year when used 
consistently and correctly. 
Combined (estrogen- and progestogen-containing) hormonal contraception associated with inhibition 
of ovulationc 
• oral 
• intravaginal 
• transdermal 
• injectable 
Progestogen-only hormone contraception associated with inhibition of ovulationc 
• oral 
• injectable 
Sexual abstinence 
Sexual abstinence is considered a highly effective method only if defined as refraining from 
heterosexual intercourse during the entire period of risk associated with the study intervention. The 
reliability of sexual abstinence needs to be evaluated in relation to the duration of the clinical trial 
and the preferred and usual lifestyle of the participant. 
Effective Methodsd That Are Not Considered Highly Effective Failure rate of ≥1% per year when 
used consistently and correctly. 
• Progestogen-only oral hormonal contraception where inhibition of ovulation is not the 
primary mode of action 
• External or internal condom with or without spermicide 
• Cervical cap, diaphragm, or sponge with spermicide 
• A combination of external condom with either cervical cap, diaphragm, or sponge with 
spermicide (double-barrier methods)c 
Note: Periodic abstinence (calendar, symptothermal, postovulation methods), withdrawal (coitus interruptus), 
spermicides only, and lactational amenorrhea method (LAM) are not acceptable methods of contraception. 
External condoms and internal condoms should not be used together (due to risk of failure from friction). 
a. 
Contraceptive use should be consistent with local regulations regarding the use of contraceptive methods for 
those participating in clinical studies. 

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b. 
Failure rate of <1% per year when used consistently and correctly. Typical use failure rates differ from those 
when used consistently and correctly. 
c. 
External condoms must be used in addition to hormonal contraception. If locally required, in accordance with 
Clinical Trial Facilitation Group (CTFG) guidelines, acceptable contraceptive methods are limited to those 
which inhibit ovulation as the primary mode of action. 
d. 
Considered effective, but not highly effective - failure rate of ≥1% per year. 

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10.7. 
Appendix 7: CDC Case Definitions of Probable and Confirmed 
Myocarditis, Pericarditis, and Myopericarditis  
The CDC working case definition of pericarditis, myocarditis, and myopericarditis to be used in 
this clinical trial is presented in Table 15. 
Table 15: CDC Case Definitions of Probable and Confirmed Myocarditis, Pericarditis, and 
Myopericarditis  
Condition 
Definition 
Acute myocarditis 
Probable Case 
Confirmed Case 
Presence of ≥1 new or worsening of 
the following clinical symptoms:a 
• 
chest pain, pressure, or 
discomfort 
• 
dyspnea, shortness of breath, or 
pain with breathing 
• 
palpitations 
• 
syncope 
Presence of ≥1 new or worsening of 
the following clinical symptoms:a 
• 
chest pain, pressure, or 
discomfort 
• 
dyspnea, shortness of breath, or 
pain with breathing 
• 
palpitations 
• 
syncope 
OR 
OR 
Infants and children aged <12 years 
might instead have ≥2 of the 
following symptoms: 
• 
irritability 
• 
vomiting 
• 
poor feeding 
• 
tachypnea 
• 
lethargy 
Infants and children aged <12 years 
might instead have ≥2 of the 
following symptoms: 
• 
irritability 
• 
vomiting 
• 
poor feeding 
• 
tachypnea 
• 
lethargy 
AND 
AND 
≥1 new finding of 
• 
troponin level above upper limit 
of normal (any type of troponin) 
• 
abnormal electrocardiogram 
(ECG or EKG) or rhythm 
monitoring findings consistent 
with myocarditisc 
• 
abnormal cardiac function or 
wall motion abnormalities on 
echocardiogram 
• 
cMRI findings consistent with 
myocarditisd 
≥1 new finding of 
• 
Histopathologic confirmation of 
myocarditisb 
• 
cMRI findings consistent with 
myocarditis in the presence of 
troponin level above upper limit 
of normal (any type of troponin) 
AND 
AND 
• 
No other identifiable cause of 
the symptoms and findings 
• 
No other identifiable cause of 
the symptoms and findings 

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Condition 
Definition 
Acute pericarditisd 
Presence of ≥2 new or worsening of the following clinical features: 
• 
acute chest painf 
• 
pericardial rub on exam 
• 
new ST-elevation or PR-depression on ECG 
• 
new or worsening pericardial effusion on echocardiogram or MRI 
Myopericarditis 
This term may be used for patients who meet criteria for both myocarditis and 
pericarditis. 
Abbreviations: AV = atrioventricular; cMRI = cardiac magnetic resonance imaging; 
ECG or EKG = electrocardiogram; MRI=magnetic resonance imaging. 
Note: An independent Cardiac Event Adjudication Committee (CEAC) comprised of medically qualified personnel, 
including cardiologists, will review reported cases of myocarditis, pericarditis, and myopericarditis to determine if 
they meet Center for Disease Control and Prevention criteria for “probable” or “confirmed” events (Gargano et al 
2021), and provide the assessment to the Sponsor. The CEAC members will be blinded to study treatment. Details 
regarding the CEAC composition, responsibilities, procedures, and frequency of data review will be defined in the 
CEAC charter. 
a. 
Persons who lack the listed symptoms but who meet other criteria may be classified as subclinical myocarditis 
(probable or confirmed). 
b. 
Using the Dallas criteria (Aretz et al 1987). Autopsy cases may be classified as confirmed clinical myocarditis 
on the basis of meeting histopathologic criteria if no other identifiable cause. 
c. 
To meet the ECG or rhythm monitoring criterion, a probable case must include at least one of 1) ST-segment or 
T-wave abnormalities; 2) Paroxysmal or sustained atrial, supraventricular, or ventricular arrhythmias; or 3) AV 
nodal conduction delays or intraventricular conduction defects 
d. 
Using either the original or the revised Lake Louise criteria (Ferreira et al 2018). 
e. 
Adler et al 2015. 
f. 
Typically described as pain made worse by lying down, deep inspiration, or cough, and relieved by sitting up or 
leaning forward, although other types of chest pain might occur (Gargano et al 2021). 
 

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10.8. 
Appendix 8: Protocol Amendment History  
The Protocol Amendment Summary of Changes Table for the current amendment is located 
directly before the Table of Contents. 
Amendment 1, 16 January 2024 
This amendment is considered to be substantial because it impacts the design/methodology of the 
study. 
Overall Rationale for the Amendment: 
The purpose of this amendment is to add a Phase 2 Extension study (Part 2) in participants aged 
18 to <50 years to evaluate the safety, reactogenicity, and immunogenicity of two compositions 
of mRNA-1083 (
) at 4 different dose levels for each composition as 
compared to mRNA-1010
 mRNA-1283, mRNA-1273, and Fluarix®. 
The summary of changes table provided here describes the major changes made in Amendment 1 
relative to the original protocol, including the sections modified and the corresponding 
rationales. As applicable, the synopsis of Amendment 1 has been modified to correspond to 
changes in the body of the protocol. 
Summary of Major Changes from Original protocol to protocol Amendment 1: 
Section # and Name 
Description of Change 
Brief Rationale 
Title Page, Signature Page, 
Protocol Amendment 
Summary of Changes, Header 
Updated the protocol version and date, as 
applicable. 
To reflect the current 
version. 
Section 1.1 (Protocol 
Synopsis) 
Protocol synopsis was updated to align 
with changes in the relevant sections of the 
protocol. 
To align with changes 
in relevant sections of 
protocol. 
Section 1.2 (Schema) 
Study schema was divided into two parts. 
Part 2 study schema was added. 
To provide the study 
schema for each part of 
the study. 
Section 1.3 (Schedule of 
activities) 
Part 2 SOA was added 
To provide the 
assessments for Part 2 
of the study. 
Section 2 
Text has been included to clarify that the 
study is now divided into 2 parts. Details 
about Part 2 of the study are added. 
Table 4 was added to provide description 
of vaccines that are used in Part 2 of the 
study. 
Text regarding the mRNA-1083 vaccines 
used in Part 2 of the study was updated.  
To give general update 
on the how the study is 
divided into 2 parts. 
 
To give clarity on 
vaccines that will be 
used in Part 2 of the 
study. 
Section 2.1.1 (Risk 
assessment) 
Text was updated to include details about 
the interim analysis for Part 1 of the study. 
To provide updated 
data. 
CCI
CCI

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Section # and Name 
Description of Change 
Brief Rationale 
Also, details regarding the completed 
Phase 1/2 study for mRNA-1010 was 
added 
Section 2.1.2 (Benefit 
assessment) 
Text was updated vaccines that are being 
administered to the participant and their 
intended benefit 
To clarify on the 
vaccines that are being 
administered 
Section 2.1.3 (Overall 
Benefit/Risk conclusion) 
Details regarding the completed study for 
mRNA-1010 and interim analysis for 
mRNA-1083 Part 1were added 
To provide updated 
data 
Section 3 (Objectives and 
endpoints) 
New section (Part 2) has been created to 
provide the objectives and endpoints of the 
newly added Phase 2 part of the study. 
Section 3 now includes 2 subsections to 
separate objectives for the 2 study parts 
(Phase 1/2 and Phase 2). 
The originally planned objectives and 
endpoints (for the Phase 1/2 part) are now 
tabulated under Section 3.1 (Phase 1/2). 
Provided the objectives 
and endpoints of the 
Phase 2 part of the 
study. 
Section 4.1 (General design) 
Added design, duration, randomization, 
treatment groups, and dosing, assessment 
procedures for Part 2 of the study. 
Provided information 
on the specific Part 2 of 
the study. 
Section 4.3 (Justification for 
Dose) 
Updated the number of participants who 
were dosed with mRNA-1283  
To provide updated 
data 
Section 5 (Study Population) 
Added inclusion and exclusion criteria for 
Part 2 Section 5.2.1 and Section 5.2.2, 
respectively. 
Inclusion criteria 6 for Part 1 was revised 
to update use of contraception from 
adequate to highly effective. 
Provided a list of the 
inclusion and exclusion 
criteria for participant 
eligibility for Part 2. 
To align with the 
appendix 10.6 which 
gives highly effective 
methods of 
contraception. 
Section 6 (Study interventions 
and concomitant therapy) 
Section 6.1 (Study 
interventions administered) 
Section 6.2 (Preparation, 
handling, storage, and 
accountability) 
Text has been updated to include 
information on the IPs administered in Part 
2 of the study. 
Details for the clinical study materials 
were removed. 
Provided information 
on the IPs administered 
in the Part 2. The 
instructions on storage, 
handling, preparation, 
processing, and 
accountability of the 
products administered 
were removed, as they 
are available in a 
Pharmacy Manual. 

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Section # and Name 
Description of Change 
Brief Rationale 
Section 6.10.3 (Prohibited 
therapy) 
Text was updated from 
“Immunosuppressants administered 
chronically (more than 14 days in total) 
during the clinical trial period. For 
corticosteroids, ≥10 mg/day of prednisone 
or equivalent is not permitted. Inhaled, 
nasal, and topical steroids are allowed” to 
“Immunosuppressants administered during 
the clinical trial period. For corticosteroids, 
≥10 mg/day of prednisone or equivalent is 
not permitted. Inhaled, nasal, and topical 
steroids are allowed.” 
To provide clarity on 
the 
immunosuppressants 
that are prohibited. 
Section 8.2 (Immunogenicity 
Assessments), Section 8.3 
(Safety Assessments) and 
Section 8.3 (Biomarkers) 
Text has been updated to include safety, 
immunogenicity, and biomarker 
assessments to be performed for Part 2 of 
the study. 
Provided text on the 
assessments and 
procedures planned for 
Part 2 of the study. 
Section 9.3 (Sample Size 
Determination) 
A sample size of 520 participants (40 
participants in each of the 13 arms) is 
planned for the Part 2 and corresponding 
text has been added. 
Added per the addition 
of the Part 2 of the 
study. 
Section 9.5.2 (Efficacy 
Analysis) 
The efficacy analysis will be limited to 
Part 1 of the study. 
Text was updated from “Efficacy analyses 
will be performed on the FAS” to 
“Analyses of RT-PCR-confirmed protocol-
defined ILI and RT-PCR-confirmed 
symptomatic SARS-CoV-2 (COVID-19) 
will be performed on the FAS.”  
To provide clarity of 
the efficacy analysis 
being performed will 
be limited to Part 1. 
Section 9.6 (Planned 
Analyses) 
Added text for the planned IA for Part 2 of 
the study. 
To provide information 
on the IA for Part 2 of 
the study. 
Section 10.2 (Clinical 
laboratory tests) 
Table title was updated to clarify that the 
clinical laboratory tests will be performed 
in both Part 1 and Part 2. 
Added per the addition 
of the Part 2 of the 
study. 
Section 10.6 (Contraceptive 
and Barrier guidance) 
Contraception guidance was updated from 
adequate to highly effective. 
To align with available 
contraception guidance. 
Throughout the protocol 
Minor formatting and edits were made for 
consistency. 
Minor formatting and 
edits were made for 
consistency and clarity. 
 
 

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