Using BCG Vaccine to Enhance Non-specific Protection of Health Care Workers During the COVID-19 Pandemic. A Randomized Controlled Multi-center Trial
Phase: PHASE3
Conditions: COVID-19, Non-specific Effects of Vaccines, Morbidity, Absenteeism, Heterologous Immunity
Sponsor: Bandim Health Project

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
 
Using BCG vaccine to enhance non-specific protection of health care workers during 
the COVID-19 pandemic. A randomized controlled multi-center trial. 
(BCG-DENMARK-COVID) 
 
Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
PROTOCOL SIGNATURE SHEET 
 
 
Name
Signature
Date
Sponsor: 
Christine Stabell Benn, MD, Prof. 
University of Southern Denmark 
Clinical Institute, OPEN 
Bandim Health Project 
Studiestræde 6, 1455 Copenhagen K 
 
 
 
 
 
20-04-2021 
Coordinating Principal Investigator:
Anne Marie Rosendahl Madsen, MD 
University of Southern Denmark 
Clinical Institute, OPEN 
Heden 16, 5000 Odense C 
 
 
 
20-04-2021

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
 
 
Protocol title 
Using BCG vaccine to enhance non-specific 
protection of health care workers during the 
COVID-19 pandemic. A randomized controlled 
multi-center trial. 
Protocol ID
BCG-DENMARK-COVID
Short title
BCG vaccine for healthcare workers against COVID-19 
EudraCT number
2020-001888-90
Version
5.3
Date
20-04-2021 
Sponsor
Christine Stabell Benn 
OPEN 
Department of Clinical Research, 
University of Southern Denmark 
Principal Investigator (PI) 
Anne Marie Rosendahl Madsen, MD, PhD student 
OPEN 
Department of Clinical Research, 
University of Southern Denmark 
Investigator 
Frederik Schaltz-Buchholzer, MD, PhD Fellow 
Department of Clinical Research, 
University of Southern Denmark 
Collaborators at participating hospitals:
Odense Universityhospital, Odense 
and Svendborg
Isik Somuncu Johansen, Dep. of Infectious Diseases, 
Odense. 
Hvidovre/Amager/Glostrup Hospital
Thomas Lars Benfield, Dep. of Infectious Diseases, 
Hvidovre. 
Aarhus Universitetshospital, Skejby 
Christian Wejse, Dep. of Infectious Diseases, Skejby. 
Lillebælt Hospital, Kolding, Vejle 
Poul-Erik Kofoed, Pediatric department, Kolding. 
Sønderjylland Hospital, Aabenraa, 
Sønderborg 
Christian Backer Mogensen, Dep. of Medicine, Aabenraa. 
Herning and, Holstebro Hospitals 
Lars Skov Dalgaard, Dep. of Medicine, Herning. 
North Zealand Hospital, Hillerød 
Ellen Løkkegaard, Dep. of Gynecology and bstetrics, 
Hillerød. 
Bispebjerg and Frederiksberg 
Hospital 
Sisse Ditlev, laboratory department, Bispebjerg. 
Esbjerg Hospital 
Morten Bjerregaard-Andersen, Dep. of Medicine, Esbjerg.
 
 Independent statistician 
Aksel Georg Jensen, University of Copenhagen 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
Pharmacy 
Hospital Pharmacy of Funen 
Odense Universitetshospital 
Solfaldsvej 38, 5000 Odense C 
GCP monitor 
 
GCP unit
Odense University Hospital 
J. B. Winsløws Vej 19, 2. sal 
5000 Odense C
Other collaborators:
Odense Patient data Explorative 
Network (OPEN) 
Odense University Hospital, University of Southern 
Denmark 
J. B. Winsloews Vej 9 a, 3  
5000 Odense C
Department of Clinical Immunology, 
Odense University Hospital 
Odense University Hospital 
J.B. Winsloews Vej 4, 
5000 Odense C 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
       LIST OF ABBREVIATIONS AND RELEVANT DEFINITIONS 
 
ABR 
General Assessment and Registration form (ABR form), the application form that is 
required for submission to the accredited Ethics Committee 
AE 
Adverse Event 
AR
Adverse Reaction
BCG 
Bacillus Calmette-Guérin 
CA
Competent Authority
CCMO
COVID-19 
Central Committee on Research Involving Human Subjects
Coronavirus Disease, i.e. the disease caused by SARS-CoV-2. 
CV
DKMA 
Curriculum Vitae
Danish Medicines Agency 
EC
The regional Committees on Health Research Ethics for Southern Denmark
EU 
European Union 
EudraCT
European drug regulatory affairs Clinical Trials
GCP 
Good Clinical Practice 
GDPR
General Data Protection Regulation 
HCW 
Health Care Workers 
B 
Investigator’s Brochure 
IC 
Informed Consent
IMP 
Investigational Medicinal Product
IMPD 
PI 
Investigational Medicinal Product Dossier 
Primary Investigator 
(S)AE 
(Serious) Adverse Event 
SPC 
Summary of Product Characteristics
Sponsor 
The sponsor is the party that commissions the organization or performance of the 
research, for example a pharmaceutical company, academic hospital, scientific 
organization or investigator. A party that provides funding for a study but does not 
commission it is not regarded as the sponsor but referred to as a subsidizing party. 
SUSAR 
Suspected Unexpected Serious Adverse Reaction
WHO 
World Health Organization 
WMO 
Medical Research Involving Human Subjects Act 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
 
 TABLE OF CONTENTS 
 
SUMMARY 
8 
BACKGROUND 
9-11 
Known side effects and risks associated with BCG 
11 
OBJECTIVES 
11 
HYPOTHESIS 
11 
PROJECT GROUP 
12 
METHODS 
12-17 
Study design and follow-up 
12-13 
Study population 
13 
Inclusion criteria 
14 
Exclusion criteria 
14 
TREATMENT OF SUBJECTS 
14 
STUDY PROCEDURES 
15-16 
Before participation 
15 
Day of enrolment 
15 
Randomization, blinding and treatment allocation 
15 
Day 0 till end of trial 
16 
End of trial 
16 
Non-responders 
16 
Withdrawal of individual subjects 
16 
ENDPOINTS AND STUDY PARAMETERS 
17 
STATISTICAL ANALYSIS 
17-18 
SAMPLE SIZE CALCULATION 
18 
Premature termination of the study 
19 
SAFETY REPORTING 
19 
Adverse events (AEs) 
19 
Serious adverse events (SAEs) 
20-21 
Serious adverse reactions (SARs) and suspected unexpected 
serious adverse reactions (SUSARs) 
20-21 
Follow-up of adverse events 
21 
ETHICAL CONSIDERATIONS 
21 
Benefits and risks assessment 
21-22 
Compensation for injury 
22 
ADMINISTRATIVE ASPECTS, MONITORING AND PUBLICATION 
23-24 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
 
Monitoring and Quality Assurance 
23 
End of trial 
23 
Public disclosure and publication policy 
24 
MAJOR MILESTONES 
25 
PERSPECTIVES 
25 
REFERENCES 
26 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
SUMMARY 
 
Background: The virus SARS-CoV-2 spreads rapidly throughout the world. The epidemic 
challenges the available hospital capacity, and this will be augmented by absenteeism of 
healthcare workers (HCW). HCW are at high risk, currently HCW constitute 20% of all the COVID- 
19 cases in Denmark. Strategies to prevent absenteeism of HCW are therefore urgently needed. 
Bacille Calmette-Guérin (BCG) is a vaccine against tuberculosis, with protective non-specific 
effects against other infections; significant reductions in morbidity and mortality have been 
reported, and a plausible immunological mechanism has been identified: “trained innate 
immunity”. We hypothesize that BCG vaccination can reduce HCW absenteeism during the 
COVID-19 epidemic. 
Objectives: Primary objective: To reduce absenteeism among HCW at risk of getting infected and 
transmitting infection during the COVID-19 epidemic. Secondary objective: To reduce the 
number of HCW that are infected with SARS-CoV-2 during the COVID-19 epidemic and to reduce 
the number of hospital admissions amongst HCW during the COVID-19 epidemic. 
Study design: A placebo-controlled single-center randomized controlled trial. 
Study population: 1500 HCW (nurses, assistant nurses, assistants, porters, physicians and other 
staff working at hospitals). 
Intervention: Participants will be randomized 1:1 to intradermal administration of a standard 
dose of BCG vaccine or placebo (saline). 
Main study parameters/endpoints: Primary endpoint: Number of days of (unplanned) 
absenteeism for any reason. Secondary endpoints: Number of days of (unplanned) absenteeism 
because of documented COVID infection. Cumulative incidence of hospital admissions. 
Risk for participants and impact: Based on previous experience and randomized controlled trials 
in adult and elderly individuals, the risks of BCG vaccination are considered low. The objective of 
this trial is to evaluate the potential beneficial effects of BCG vaccination through a lower work 
absenteeism rate of HCW and/or a mitigated clinical course of COVID infection. The primary 
endpoint and frequent interim analyses facilitate maximum efficiency of the trial, so that results 
can inform policy making during the ongoing epidemic. 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
BACKGROUND 
 
On 30 December 2019, a novel enveloped RNA beta-coronavirus was detected from a patient 
with pneumonia of unknown etiology in Wuhan, the capital city of Hubei province, China. The 
pathogen was named the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) [1,2]. 
Since beginning of 2020, SARS-CoV-2 spread rapidly throughout China and the rest of the world, 
with the first detected case in Denmark on 27 February 2020. 
The estimated basic reproduction number (R0) of SARS-CoV-2 is 2.2, i.e. on average, each 
infected person spreads the infection to an additional two persons. SARS-CoV-2 is being 
transmitted via droplets during close unprotected contact between people [1]. According to the 
WHO, as of 8 April 2020, 1,435,091 laboratory-confirmed SARS-CoV-2 cases were established. 
Health-care workers face an elevated risk of exposure to - and infection with - SARS-CoV-2. This 
reflects a serious threat to hospital personnel capacity in Denmark as the number of COVID-19 
patients that require hospital care may well exceed the capacity of hospital personnel. Even if 
further mobilization of hospital personnel is possible to some extent, it is imperative to ensure 
the safety, health and fitness of hospital personnel in order to safeguard continuous patient care. 
Strategies to prevent SARS-CoV-2 infection or to mitigate its clinical consequences are therefore 
urgently needed. To date, no curative or protective treatments have been identified yet despite 
ongoing trials. 
BCG vaccine: Bacillus Calmette-Guérin (BCG) was developed as a vaccine against tuberculosis, 
but our group has shown that it can protect against death from other infections, it has what we 
have called non-specific effects (NSEs) [3]. In clinical studies, BCG vaccination was associated 
with less child mortality, mainly as a result of reduced neonatal sepsis and respiratory infections 
[4–6]. In a WHO-commissioned meta-analysis, BCG was associated with 42% (95%CI: 24-55%) 
lower child mortality [7]. 
Non-specific effects (NSEs): NSEs of BCG are not limited to children. An Indonesian trial with 34 
subjects has shown that consecutive BCG vaccination for 3 months reduced the incidence of 
acute upper tract respiratory infections by 80% (95%CI=22-95%) [8]. It has been recently 
demonstrated that the non-specific beneficial effects of BCG vaccination are due to epigenetic 
and metabolic reprogramming of innate immune cells such as myeloid cells and NK cells, leading 
to an increased antimicrobial activity, a process termed ‘trained immunity’ [9]. Upon stimulation 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
with a pathogen, the innate immune system becomes primed and is able to react faster and 
more efficiently to a secondary (and non-related) stimulus. In experimental studies, BCG has 
been shown to protect against not only bacterial and fungal infections, but against viral 
infections such as influenza as well [10]. Furthermore, among humans receiving yellow fever 
vaccine virus, those who had received BCG had – compared to placebo treated subjects – lower 
viral load, and improved anti-viral responses (Figure 1) [11]. The observed effects are proposed 
to be due to modulation of the human innate immune system through ‘trained immunity’ and 
are lasting for at least one year [9]. 
 
Figure 1. Healthy volunteers were injected with either placebo (n=15) or BCG (n=15). One month 
later all volunteers were injected with yellow fever vaccine. Viremia was assessed on day 5 after 
yellow fever vaccination by PCR in the blood. BCG vaccination significantly decreased the viremia 
in the circulation [11]. 
 
 
 
 
Based on the capacity of BCG to 1) reduce the incidence of morbidity and mortality due to 
infectious diseases in children and perhaps in the elderly; 2) exert antiviral effects in 
experimental models; and 3) reduce viremia in an experimental human model of viral infection, 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
we hypothesize that BCG vaccination may induce (partial) protection against susceptibility to 
and/or severity of COVID-19. This study will evaluate the efficacy of BCG to improve the clinical 
course of COVID-19 and to prevent absenteeism. 
A randomized controlled trial provides the highest validity for this research question. Given the 
immediate threat of the COVID-19 epidemic the trial has been designed as a pragmatic study 
with a highly feasible primary endpoint, that can be continuously measured. This allows for the 
most rapid identification of a beneficial outcome that would allow other HCW to benefit from 
the intervention if it is demonstrated to be effective. We have therefore chosen unplanned 
absenteeism from work as primary outcome, in line with an ongoing clinical trial of BCG in the 
Netherlands. 
Known side effects and risks associated with BCG: The BCG vaccine has been used for almost 
100 years and is now part of more than 100 countries’ childhood immunization programs. In 
Denmark, we stopped BGC in the 1980s, as the tuberculosis risk decreased. The following side 
effects are common: Redness and swelling of the skin where the vaccine is given, swollen lymph 
nodes up to 4 weeks after the vaccine, and a small ~5 mm scar. Because the vaccine has been 
known and used for many years, we also know the rare side effects: Less than 1 out of 100 can 
get headaches, fever or wounds above the vaccination site. Less than 1 in 1,000 can get a boil 
over the vaccination site, and less than 1 in 25,000 can get bone inflammation, lymph node 
inflammation or severe allergic reaction. 
 
OBJECTIVES 
 
Primary objective: To reduce absenteeism among HCW during the COVID-19 epidemic. 
Secondary objective: To reduce the number of HCW that are infected with SARS-CoV-2 during the 
COVID-19 epidemic and to reduce the number of hospital admissions amongst HCW during the 
COVID-19 epidemic. 
 
HYPOTHESIS 
BCG vaccination of HCW will reduce absenteeism by 20% over a period of 6 months. 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
PROJECT GROUP 
 
Christine Stabell Benn (MD, DMSc), Peter Aaby (DMSc), Anne Marie Rosendahl Madsen (MD, PhD 
student), Frederik Schaltz-Buchholzer (MD, PhD student), all from University of Southern 
Denmark. Mihai Netea (MD, DMSc) Radboud Medical Centre, Nijmegen, The Netherlands. Tyra 
Groove Krause (MD, PhD) Statens Serum Institut, and the collaborators from each participating 
hospital. 
 
METHODS 
 
Study design and follow-up: A placebo-controlled adaptive single center randomized controlled 
trial with inclusion of study participants at several geographic locations. See figure 2 for the 
logistics of the study. Since the IMP, the BCG vaccine, is used in this study on another indication 
than the one it has been approved for, this is classified as a phase III study.  
 
Table 1. Overview of participating hospitals: 
 
 
Participating hospitals 
Hospital collaborator 
Participants enrolled
Odense 
Universitetshospital/ 
Svendborg Sygehus 
Isik Somuncu Johansen
92 
Sygehus Lillebælt, 
Kolding/Vejle 
Poul-Erik Kofoed
145
Hvidovre/Amager/Glostrup 
Hospital 
Thomas Lars Benfield
322
Nordsjællands Hospital, 
Hillerød 
Ellen Løkkegaard 
85  
Aarhus Universitetshospital
Christian Wejse
47
Regionshospitalet 
Herning/Holstebro 
Lars Skov Dalgaard
102
Sygehus Sønderjylland
Christian Backer Mogensen
139 
Bispebjerg and 
Sisse Bolm Ditlev
189

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
Frederiksberg Hospital
Esbjerg Sygehus
Morten Bjerregaard-Andersen
112 
 
 
Figure 2: Study design of the BCG-DENMARK-COVID trial: 
 
 
 
 
 
 
Study population: As the COVID-19 epidemic has already started in Denmark, our intention is to 
start as soon as possible. Recruitment of study participants will take place at hospitals where the 
risk of exposure to SARS-CoV-2 is high. For an overview of participating hospitals, see table 1. 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
Inclusion criteria: In order to be eligible to participate in this study, a subject must meet the 
following criteria: Adult (≥18 years); HCW working at hospitals. 
Exclusion criteria: The exclusion criteria will be assessed at the recruitment interview. We will 
not use the electronic patient records to check exclusion criteria. A potential subject who meets 
any of the following criteria will be excluded from participation in this study: 
Known allergy to (components of) the BCG vaccine or serious adverse events to prior BCG 
administration; Known active or latent infection with Mycobacterium tuberculosis (M. 
tuberculosis) or other mycobacterial species; Previous M. tuberculosis infection; Previous 
confirmed COVID-19 infection; Fever (>38 C) within the past 24 hours; Suspicion of active viral or 
bacterial infection; Pregnancy; Breastfeeding; Vaccination with other live attenuated vaccine 
within the last 4 weeks; Severely immunocompromised subjects. This exclusion category 
comprises a) subjects with known infection by the human immunodeficiency virus (HIV-1); b) 
subjects with solid organ transplantation; c) subjects with bone marrow transplantation; d) 
subjects under chemotherapy; e) subjects with primary immunodeficiency; f) treatment with any 
anti-cytokine therapies. g) treatment with oral or intravenous steroids defined as daily doses of 
10 mg prednisone or equivalent for longer than 3 months; Active solid or non-solid malignancy or 
lymphoma within the prior two years; Direct involvement in the design or the execution of the 
BCG-DENMARK-COVID study; Employed to the hospital < 22 hours per week. 
Treatment of subjects: Participants will be randomized 1:1 to receiving one intradermal BCG 
vaccine or placebo. Participants that are randomized in the active arm will receive a BCG vaccine 
(BCG-Denmark, AJ Vaccines, http://www.produktresume.dk/AppBuilder/login.html). The vaccine 
batches provided by AJ Vaccines for this study has not been released for sale in Denmark, but has 
been released by WHO, certificate number: 2019052989, 2019053438 and 2019093213. The 
product is identical to the vaccine released for Denmark with respect to production, control and 
contents. AJ Vaccines will send the vaccines to Hospital Pharmacy of Funen. The pharmacy will 
assure correct control and storage of the vaccines and will release the vaccines to the study 
according to GCP. A collaboration agreement will be made with the pharmacy. Placebo will be 
0.1 ml sterile 0.9 % NaCl, which has a similar color as the resuspended BCG vaccine. 
Description of route of administration and dosage: 
All participants will receive one injection at inclusion. No further treatment of study participants 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
will take place. BCG will be administered in the right upper arm, intradermally, 0.1 ml of the 
suspended vaccine. Placebo will be administered in the right upper arm, intradermally, 0.1 ml of 
sterile 0.9 % NaCl solution. 
STUDY PROCEDURES 
Before participation: HCW (possible subjects) will be informed about the study by their local 
contact person/hospital collaborator. Also written information about the study will be sent to 
possible subjects by email. Subjects that are interested will receive additional study information 
(participant information and informed consent form) and are scheduled for an appointment with 
one of the investigators. Screening of possible subjects, information, enrolment procedures and 
follow up will be done by the investigators from University of Southern Denmark or trained MD’s 
to whom the task has been delegated, at all locations.  
The subject visits the vaccination site (a designated room in the hospital), where he/she receives 
oral and written information by the investigator. Eligibility criteria will be checked. For all women 
of childbearing potential, pregnancy will be excluded with a urine HCG test according to CTFG’s 
’Recommendations related to contraception and pregnancy testing in clinical trials’. Women of 
childbearing potential are defined in this study as all women above 18 years of age (according to 
the inclusion criteria), who has not reached menopause. Women will be asked about this at the 
inclusion interview. Before informed consent is be obtained, subjects are offered 24 h of 
reflection time. 
See figure 3 below for flowchart of interventions. 
Day of enrolment (Day 0): Day 0: Participants fill in a short questionnaire regarding baseline 
characteristics. The entire follow-up will be performed electronically using REDCap. An email 
with a link to the questionnaire will be sent to the participants weekly. At enrolment participants 
will be informed about this procedure. A blood sample of 5 ml will be drawn for subsequent 
testing for SARS-CoV-2 antibodies. 
Randomization, blinding and treatment allocation: Participants will be randomized to BCG or 
placebo in a 1:1 ratio. Randomization will be done centrally using the REDCap tool with 
stratification per hospital and by sex and age groups (+/- 45 years of age) in randomly selected 
block sizes of 4 and 6. 
The BCG vaccine will be administered to participants at all sites by the investigators, who have 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
been trained in intradermal injections. Participants will be blinded to treatment. The participant 
will be asked to leave the room while the vaccine/placebo is prepared. Once ready for injection, 
the vaccine and placebo will look similar, and the participant will not be able to tell the 
difference. The physicians administering the BCG vaccine or placebo will not be blinded. In case 
of serious adverse events, the participant can be unblinded after consultation with the PI or 
sponsor. The end of the trial is defined as whichever comes latest: the last patient’s last 
registration in the online data collection, or 180 days. When the study is ended, all participants 
receive an email with information about the intervention that they have received (BCG/placebo).  
Day 0 till end of trial (weekly): Short electronic questionnaire regarding work absenteeism, 
symptoms and side effects. Link to the questionnaire will be sent every week by email to the 
participants through REDCap. We will use the participants official work email or e-boks for 
security reasons. In case a participant reports acute respiratory symptoms indicating COVID-19, 
he or she will be tested depending on test availability. 
End of trial: Participants are asked to fill in a final questionnaire. A blood sample of 5 ml will be 
drawn for subsequent testing for SARS-CoV-2 antibodies. 
 
Figure 3: Flowchart, interventions. 
 
 
 
Non-responders: Day 0 till end of study: In case of not filling in the questionnaire for ≥10 days, 
the participant receives a notification. Participants with incomplete follow-up despite notification 
will be telephoned with the request to complete the follow-up data. In case the participant does 
not answer the telephone, information on the participant will be retrieved from the Danish 
National Discharge Register regarding hospital admission, ICU admission and outcomes. An 
explicit permission for this procedure will be requested from the participant at informed consent. 
Withdrawal of individual subjects: Subjects can leave the study at any time for any reason if 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
they wish to do so, without any consequences. The investigator can decide to withdraw a subject 
from the study for urgent medical reasons. A participant will only be replaced in case of 
withdrawal before the administration of BCG vaccine/placebo. The participant will be asked to 
give a blood sample for SARS-CoV-2 antibody testing at end of the study period – even if they for 
some reason leave the study prematurely.  
ENDPOINTS 
Main study endpoint: Number of days of unplanned absenteeism for any reason. 
Secondary study endpoints: The cumulative incidence of documented COVID and the cumulative 
incidence of hospital admission for any reason. Number of days of (unplanned) absenteeism due to 
infections; Number of days of (unplanned) absenteeism due to respiratory infections; Cumulative 
incidence of infectious disease episodes, in particular respiratory infections; Cumulative incidence of 
infectious disease hospital admissions, in particular respiratory infections. 
Furthermore, in line with the Dutch trial, the following endpoints will be assessed: 
The number of days of unplanned absenteeism, because of documented SARS-CoV-2 infection; 
The number of days of absenteeism, because of imposed quarantine as a result of exposure to 
SARS- CoV-2; The number of days of absenteeism, because of imposed quarantine as a result of 
having acute respiratory symptoms, fever or documented SARS- CoV-2 infection; The number of 
days of unplanned absenteeism because of self-reported acute respiratory symptoms; The 
number of days of self-reported fever (≥38 °C); The number of days of self-reported acute 
respiratory symptoms; The cumulative incidence of self-reported acute respiratory symptoms; 
The cumulative incidence of death for any reason; The cumulative incidence of death due to 
documented SARS- CoV-2 infection; The cumulative incidence of Intensive Care Admission for 
any reason; The cumulative incidence of Intensive Care Admission due to documented SARS- 
CoV-2 infection; The cumulative incidence of Hospital Admission due to documented SARS-CoV-2 
infection. 
 
STATISTICAL ANALYSIS 
Data will be reported quantitatively. All analyses will be performed from the intention-to-treat 
principle. Missing data will be dealt with by multiple imputation using the mice package in R.  
Primary study parameter: The primary endpoint, work absenteeism for any reason, will be 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
reported as the average proportion of sick days with standard deviation. It will be analyzed as 
counts per week (i.e. multiple observations per subject) using a Bayesian negative binomial 
regression with a random intercept per participant and a fixed effect for BCG, hospital, 
observation week, and number of average workdays per week. The brm function from the R 
package “brms” will be used for fitting the negative binomial model. The effect will be reported 
as a relative risk with 95% confidence interval (CI). Please refer to section interim analysis for 
type-1 error control and power. 
Secondary study parameters: Similar regression models will be used for secondary endpoints: 
Number of days of unplanned absenteeism because of documented SARS-CoV-2 infection; 
number of days of self-reported fever: negative binomial model, similar to the primary endpoint. 
Documented infection with SARS-CoV-2, death for any reason, death due to documented SARS-
CoV-2 infection, cumulative incidence of Intensive Care Admission for any reason, cumulative 
incidence of Intensive Care Admission due to documented SARS-CoV-2 infection, cumulative 
incidence of Hospital Admission for any reason, cumulative incidence of Hospital Admission due 
to documented SARS-CoV-2 infection: a Cox proportional hazards model will be used for these 
endpoints. When applicable (i.e. in the event that one or more participants have died during the 
follow-up period) a competing events analysis will be performed in addition (Fine & Gray model). 
Other study parameters: Continuous baseline characteristics will be reported as mean and 
standard deviation or median and inter-quartile range, as appropriate. Categorical baseline 
characteristics will be reported as count and percentage. No statistical testing for baseline 
characteristics will be performed. 
Participants will be followed until receipt of another vaccine, but data will also be analyzed after 
receipt of another vaccine in order to assess potential interactions.  
Interim analysis: Every month, an interim analysis will be conducted by the independent 
statistician of the trial. The primary endpoint will be analyzed as described above. The Bayesian 
model yields a posterior distribution of the relative risk. The posterior probability of the 
superiority hypothesis (RR < 1) will be calculated as well as the posterior probability of the futility 
hypothesis (RR > 0.7). If during any of the interim analyses, the posterior probability of 
superiority is > 0.995 or the posterior probability of futility is > 0.99, a conclusion is reached, and 
the trial will be stopped. These posterior probability breakpoints have been chosen such that the 
type-1 error rate is <0.025 (similar to a two-sided alpha of 0.05) and the power of detecting 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
superiority is >90% if the true RR is 0.7. 
Monthly, the following secondary endpoints will be reported to the steering group unblinded: 
‘the cumulative incidence of hospital admission, Intensive Care Admission or death’. 
 
SAMPLE SIZE CALCULATION 
Interim analyses are done by an independent statistician every month to monitor effects on the 
primary outcome: days of sickness absence. If the posterior probability of a positive effect 
(relative risk (RR) <1) exceeds 0.995, the study will be discontinued, and the conclusion reported 
to the authorities as soon as possible. The parallel Dutch study and participation in this project 
group by Prof. Netea from The Netherlands will enable combined analysis that will strengthen 
the conclusions and increase the power to analyze the secondary outcomes and more rare 
outcomes as intensive hospitalization. As this is an adaptive sample size, the final sample size and 
follow-up duration is subject to the percentage of absenteeism during the study period, variation 
in absenteeism between participants, and the true effect of BCG vaccine. 
 
PREMATURE TERMINATION OF THE STUDY 
Based on the interim analyses, the Steering group consisting of the sponsor, the PI and the 
collaborators from the seven participating hospitals can recommend terminating the trial 
prematurely. The final decision is with the sponsor. 
 
 
SAFETY REPORTING 
Temporary halt for reasons of subject safety: In accordance to section 10, subsection 4, of the 
Medical Research Involving Human Subjects Act (WMO), the sponsor will suspend the study if 
there is sufficient ground that continuation of the study will jeopardize subject health or safety. 
The sponsor will notify the EC and the DKMA without undue delay of a temporary halt including 
the reason for such an action. The study will be suspended pending a further positive decision by 
the EC and the DKMA. The investigator will take care that all subjects are kept informed. 
Adverse events (AEs): Adverse events are defined as any undesirable experience occurring to a 
subject during the study, whether or not considered related to the investigational product, the 
placebo or the trial procedures. Participants can fill in adverse events in REDCap using the online 

20
BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
application. All adverse events will be reported to the relevant authorities for 7 days after 
inclusion. 
Serious adverse events (SAEs): A serious adverse event is any untoward medical occurrence or 
effect that: 
- Results in death; 
- Is life threatening (at the time of the event); 
- Requires hospitalization or prolongation of existing inpatients’ hospitalization; 
- Results in persistent or significant disability or incapacity; 
- Is a congenital anomaly or birth defect; 
Or any other important medical event due to the intervention based upon appropriate 
judgement by the investigator. An elective hospital admission will not be considered as a serious 
adverse event. Participants will be asked about the occurrence of SAE’s weekly in the 
questionnaire. In case of a SAE, dependent on the symptoms of the participant, he/she will be 
contacted by the investigator and if necessary, admitted to the hospital. The condition of the 
participant will be evaluated by the investigator, who can decide to un-blind if deemed 
necessary. In case a participant does not fill in the online questionnaire, he or she will be called 
by the investigator to collect data on SAE’s. 
The investigator will notify sponsor within 24 hours after first knowledge of any SAEs, in order for 
sponsor to assess whether it is a SUSAR.  
Serious adverse reactions (SARs) and suspected unexpected serious adverse reactions 
(SUSARs): Adverse reactions are all untoward and unintended responses to an investigational 
product related to any dose administered. The BCG vaccine SPC will be used as reference. 
Unexpected adverse reactions are SUSARs if the following three conditions are met: 
- The event must be serious (see above); 
- There must be a certain degree of probability that the event is a harmful and an undesirable 
reaction to the medicinal product under investigation, regardless of the administered dose. 
- The adverse reaction must be unexpected, that is to say, the nature and severity of the adverse 
reaction is not in agreement with the product information as recorded in the SPC. 

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
The investigator and the sponsor will report expedited the following SUSARs to the EC and the 
DKMA with consideration of the following  timeframes; Within 7 days of first knowledge for 
SUSARs that result in death or require admission to an intensive care unit followed by a period of 
maximum of 8 days to complete the initial preliminary report. All other SUSARs will be reported 
within a period of maximum 15 days after the sponsor has first knowledge of the serious adverse 
events. Reporting will be done using the eBlanket provided by the DKMA. 
- SUSARs that have arisen in the clinical trial that was assessed by the EC and DKMA; 
- SUSARs that have arisen in other clinical trials of the same sponsor and with the same medicinal 
product, and that could have consequences for the safety of the subjects involved in the clinical 
trial that was assessed by the EC and DKMA. 
The remaining SUSARs are recorded in an overview list (line-listing) that will be submitted to the 
EC at the end of trail. This line-listing provides an overview of all SUSARs from the study 
medicine, accompanied by a brief report highlighting the main points of concern. There will be 
no yearly report as the study will be completed before one year. 
The expedited reporting will occur not later than 15 days after the sponsor has first knowledge of 
the adverse reactions. For fatal or life-threatening cases, the term will be maximal 7 days for a 
preliminary report with another 8 days for completion of the report. 
Follow-up of adverse events: All AEs occurring in the first 7 days after inclusion and all SAEs, 
SARs and SUSARs will be followed until they have abated, or until a stable situation has been 
reached. Depending on the event, follow up may require additional tests or medical procedures 
as indicated, and/or referral to the general physician or a medical specialist. 
AEs will only be reported during the first 7 days after inclusion. SUSARs will be reported to the EC 
and DKMA till the end of the study. 
 
ETHICAL CONSIDERATIONS 
The study will be conducted according to the principles of the Declaration of Helsinki amended at 
the General Assembly in October 2013 and in accordance with the Medical Research Involving 
Human Subjects Act (WMO) and other guidelines, regulations and Acts. The study will be 
submitted for approval from the EC and DKMA. We will ask participants permission to access 
electronic patient records, in order to access relevant test results and information on hospital 

22
BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
admissions in the study period. We only need to access the records after the participants have 
given their consent. The participants will be informed, that their consent gives the sponsor, 
sponsors representatives, PIs, and monitoring agencies direct access to relevant health 
information from their electronic patient records. 
Benefits and risks assessment: The potential benefit for subjects randomized to the BCG-arm is 
possibly a lower risk of getting COVID-19 and a lower risk of severe illness related to COVID-19, 
which could reduce absenteeism and the risk of hospital admission. Potential risks include only 
the well-known side effects of the vaccine. The BCG vaccine SPC will be used as reference 
document. As part of the study information, participants will be informed about the possible side 
effects to the treatment, including that it is common and not treatment demanding that, 
following BCG vaccination, redness, swelling and ulceration of the skin where the vaccine is given 
will occur, that there may be swollen lymph nodes in the area some weeks after the vaccine is 
given, and that in the longer term, a small scar, approximately 5 mm diameter, will appear where 
the vaccine was given. This kind of side effects will not be reported to DKMA. 
Severe but very rare side effects are injection site abscesses, BCG lymphadenitis, disseminated 
BCG disease, osteitis, osteomyelitis, anaphylaxis, formation of keloid/lupoid, suppurative 
lymphadenitis. A complete list of known side effects can be found in the participant information 
leaflet. Subjects that receive the placebo hardly have any potential risks and no benefits. Local 
hematoma formation can occur at the site of injection. 
BCG vaccine in immunocompetent adult people is considered safe, also for persons with prior 
BCG vaccination and even in latently infected adults [12,13]. In a randomized controlled trial that 
compared revaccination with BCG versus placebo, no vaccine-related serious adverse events 
were observed in the 312 patients in the BCG arm [14]. 
Thus, the risk to and burden for the subject of BCG vaccination is estimated to be low, according 
to previous trials that have been performed with BCG vaccines [8,11,14]. It is not recommended 
to get other live attenuated vaccines within a month of BCG vaccination, unless given at the same 
time. Apart from this, no interactions are known between BCG vaccination and other medications. 
Using an adaptive design, the study aims to find a positive effect of BCG-vaccine on a population 
level, which could be applied quickly in participants allocated to placebo and implemented to 
hospitals that do not participate in the study. 
Participation in this study should in principle not be an exclusion criterion for participation in 

23
BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
other studies (for example into treatments for Coronavirus infections). Participants are informed 
that the Mantoux test for screening for tuberculosis is no longer reliable after BCG vaccination. 
The reliability of the TB-Quantiferon test is not affected by BCG-vaccination. 
Compensation for injury: The study participants are fully insured according to the Danish Patient 
Insurance Act. This insurance provides cover for damage to research subjects through injury or 
death caused by the study. Participants will not be compensated for participating in this study. 
Damage to subjects through injury or death, caused by the study or negligence of local study 
investigators, is not accountable to the principle investigator. 
 
ADMINISTRATIVE ASPECTS, MONITORING AND PUBLICATION 
Data and biological material will be registered and stored via OPEN (Open Patient data 
Explorative Network) using REDCap, OPEN Analyze and OPEN Biobank hosted by OPEN on secure 
servers in the Region of Southern Denmark. Data analysis will be done according to safety 
regulations with pseudonymized copies of data. Data will be processed and stored locked / 
inaccessible and safely in full compliance with the Data Inspectorate's Standard Terms for 
Research Projects. All source data will be kept in the electronic CRF in REDCap. The sponsor, 
investigators appointed by the sponsor, the study statistician, and monitoring agencies will be 
able to get direct access to source data. A subject identification code list based on non-traceable 
items will be used to link the data to the subject. The key to the code will be safeguarded by the 
coordinating PI on a designated secure location. 
The handling of personal data complies with the EU General Data Protection Regulation and the 
Danish Act on Implementation of the General Data Protection Regulation. 
The investigator and master file and the electronic data from the eCRF will be stored for a 
duration of 5 years. Information, data, and results that originate from this study may not be 
disclosed without the written permission of the sponsor and coordinating principal investigator. 
The blood samples will be kept in an OPEN research biobank during the study period and 
potentially remaining biological material will be stored in an OPEN biobank for 5 years after end 
of trial, allowing for the possibility that new insights may be reached during this time, which 
could be addressed in the existing material. If that is the case, ethical permission to analyze the 
samples will be applied for. After 5 years all remaining biological material will be destroyed.  

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
Monitoring and Quality Assurance: We classify this trial as a low risk study, because the 
intervention is already registered, and has been used in previous trials. The study will be 
monitored by the GCP unit at Odense University Hospital. The first monitor visit will take place 
before inclusion of the first study participant. During this visit the presence and completeness of 
the relevant Study Files will be checked. 
End of trial: The sponsor will notify the EC and DKMA about the end of the study within a period 
of 90 days. The end of the study is defined as the last patient’s last registration in the online data 
capture system. Within one year after the end of the study, the sponsor will submit a final study 
report with the results of the study, including any publications/abstracts of the study, to the EC. 
The sponsor will notify the EC and DKMA immediately of a temporary halt of the study, including 
the reason of such an action. In case the study is ended prematurely, the sponsor will notify the 
EC and DKMA within 15 days, including the reasons for the premature termination. 
Public disclosure and publication policy: The results of this study will be disclosed unreservedly 
at the end of the study. Results that are important for public health will be notified to the 
competent authorities as soon as possible. The trial will be registered in a public trial registry 
before the first patient is recruited. 
 
 
FUNDING AND MATERIAL SUPPORT 
We are currently applying for funding from various sources that support projects aiming to 
mitigate the effect of the COVID-19 pandemic. AJ Vaccines will be supplying the BCG vaccines 
free of charge. This company has had no influence on the design of the study and will not have 
influence on any aspect of analyzing, interpretation or reporting of results. None of the parties in 
the study group have any economic interest in this company. The EC will be informed about any 
further economic or other support that the project may receive. This will include the amount 
received, how it will be used and account number. 
 
MAJOR MILESTONES 
Application for Regional ethical committee submitted: April 16, 2020  
Application for EudraCT submitted: April 16, 2020 
Application for Danish Medicines Agency submitted: April 16, 2020  

25
BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
Approval from Danish Medicines Agency received: April 27, 2020. 
Approval from Regional Ethics Committee received: April 30, 2020. 
Inclusion of first participant: May 2020 
Inclusion of last participant: January 2020 
End of follow-up, last patient: July 2021  
Data analyzed: September 2021 
 
PERSPECTIVES 
In this trial the registered BCG vaccine will be used in hospital personnel as protection for 
absenteeism during the COVID pandemic. The risk of the BCG vaccine is low and only minor local 
side effects (redness, local pain) are common. The benefits of BCG vaccination based on earlier 
clinical studies are expected to be a reduction in morbidity and absenteeism of at least 20% 
compared to unvaccinated individuals, and potentially higher. These effects are mediated by the 
capacity of BCG to induce trained immunity and may represent an important tool for protection 
against SARS-CoV-2 virus infection until a specific effective vaccine is developed.

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BCG-DENMARK-COVID                                                                                              Protocol version 5.3, 20-04-2021 
EudraCT: 2020-001888-90 
 
 
 
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