cdc.gov/coronavirus

COVID-19 Vaccine Safety Monitoring 

in Children

Advisory Committee on Immunization Practices 

(ACIP)

November 2, 2021

Tom Shimabukuro, MD, MPH, MBA

Vaccine Safety Team

CDC COVID-19 Vaccine Task Force
Topics

 CDC surveillance systems and processes for monitoring vaccine 

safety in children*

 FDA, Indian Health Service (IHS), and Department of Defense (DoD) 

vaccine safety monitoring systems

 COVID-19 Vaccine Safety Technical (VaST) Work Group

* CDC continuously monitors authorized and licensed vaccines administered to children in the United States 2
CDC vaccine safety monitoring

v-safe VAERS VSD CISA Project

Full list of U.S. COVID-19 vaccine safety monitoring systems

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety.html

 COVID-19 vaccines are being administered under the most intensive vaccine safety 

monitoring effort in U.S. history

 Strong, complementary systems are in place―both new and established 

3
4

Smartphone-based active safety monitoring

http://cdc.gov/vsafe

Now available!

• Enrolling children 

• 3rd dose reporting 
5

Adding a dependent in v-safe 

 Participants can register themselves or dependents 

after dose 1, 2, or 3

 Dependents can be added, even if the primary 

smartphone account is not av-safe participant

• Parent/guardian must create a profile then add 

dependent

• Text messaging directed to parent/guardian

V-safe check in schedule: • Once a day (days 0–7) • Once a week (weeks 2

–6)

• Once a month (months 3, 6, and 12) • Schedule restarts after each dose received
6

V-safe analytic plan for children aged 5–11 years

 V-safe will aggregate data from health surveys completed on 

days 0–7 after vaccination for children aged 5–11 years

• Describe sex, median age, race/ethnicity of vaccinated children

• Describe local reactions, systemic reactions, and health impacts by 

dose received

 Compare reactogenicity profile for children aged 5–11 years 

to adolescents aged 12–17 years

 Reports to VAERS solicited by active telephone follow-up of 

v-safe participants are included in VAERS analyses
+ co-managed by

CDC and FDA

Vaccine Adverse Event 

Reporting System

http://vaers.hhs.gov

VAERS is the nation’s early warning system for vaccine safety

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VAERS accepts reports from everyone

Key strengths

 Rapidly detects potential 

safety problems 

 Can detect rare adverse 

events

Key limitations

 Passive surveillance system

 Inconsistent quality and 

completeness of information

 Reporting biases

 Generally, cannot determine 

cause and effect

Regardless of the plausibility of the vaccine causing the event or the 

clinical seriousness of the event

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VAERS prespecified adverse events of special interest*

(as of Oct 27, 2021)

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 Death

 Acute myocardial infarction

 Anaphylaxis

 Coagulopathy

• Thrombocytopenia

• Deep venous thrombosis or 

pulmonary embolism 

• Disseminated intravascular 

coagulopathy

 Guillain-Barré Syndrome (GBS)

 Kawasaki disease

 Multisystem inflammatory syndrome in 

children (MIS-C)

 Myocarditis, myopericarditis, and pericarditis

 Narcolepsy/cataplexy

 Seizure

 Stroke

 Thrombosis with thrombocytopenia syndrome 

(TTS)

 Transverse myelitis

* Assessment includes: clinician review of VAERS report, follow-up to obtain and review medical records, application 

of case definition (where case definition exists), adjudication to classify the report with respect to case definition
Particular focus on myocarditis/myopericarditis reports

 Potential reports identified by Medical Dictionary for Regulatory 

Activities (MedDRA)* standardized codes assigned to report that 

could indicate myocarditis or pericarditis

 Clinical abstraction

• Review of initial report

• Outreach to healthcare provider involved in reported patient’s care

• Request and review of medical records

• Compare abstracted data elements against CDC case definitions for 

myocarditis and pericarditis

 CDC will conduct periodic analyses of case counts and reporting 

rates and comparison of reporting rates to background

* www.medra.org 10
VSD

Vaccine

Safety

Datalink

 9 participating integrated healthcare organizations

 Data on over 12 million persons per year

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Aims:

 To monitor the safety of COVID-19 vaccines weekly using 

prespecified outcomes of interest among VSD members

 To describe the uptake of COVID-19 vaccines over time among 

eligible VSD members overall and in strata by age, site, and 

race/ethnicity

Surveillance began in December 2020

Vaccine Safety Datalink (VSD) Rapid Cycle Analysis (RCA)

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Prespecified RCA surveillance outcomes Settings Risk window

(days)

Chart 

review

Monitoring

only

Exclude if COVID-19 

in prior X days

Acute disseminated encephalomyelitis E, I 1-21, 1-42 Yes

Acute myocardial infarction – First Ever E, I 1-21, 1-42 30 days

Acute respiratory distress syndrome E, I 0-84 Yes 42 days

Anaphylaxis – First in 7 days E, I 0-1 Yes Yes

Appendicitis E, I 1-21, 1-42

Bell’s palsy – First Ever E, I, O 1-21, 1-42 30 days

Cerebral venous sinus thrombosis E, I 1-21, 1-42 Yes 30 days

Disseminated intravascular coagulation E, I 1-21, 1-42 42 days

Encephalitis / myelitis / encephalomyelitis E, I 1-21, 1-42 30 days

Guillain-Barré syndrome E, I 1-21, 1-42 Yes

Immune thrombocytopenia E, I, O 1-21, 1-42 30 days

Kawasaki disease E, I 1-21, 1-42

Multisystem inflammatory syndrome in children/adults (MIS-C/MIS-A) E, I 0-84 Yes

Myocarditis / pericarditis – First in 60 Days E, I 1-21, 1-42 Yes (subgroup) 30 days

Narcolepsy / cataplexy E, I, O 0-84 Yes

Pulmonary embolism – First Ever E, I 1-21, 1-42 30 days

Seizures E, I 1-21, 1-42 30 days

Stroke, hemorrhagic E, I 1-21, 1-42 30 days

Stroke, ischemic E, I 1-21, 1-42 30 days

Thrombosis with thrombocytopenia syndrome – First Ever E, I 1-21, 1-42 30 days

Thrombotic thrombocytopenic purpura E, I 1-21, 1-42 30 days

Transverse myelitis E, I 1-21, 1-42 Yes

Venous thromboembolism – First Ever E, I, O 1-21, 1-42 30 days

VSD COVID-19 vaccine RCA outcomes

Abbreviations: E = emergency department; I = inpatient; O = outpatient 13
VSD analytic strategy for the 5–11-year-old age group

 Statistical analysis will be similar to what is being done for other age groups but will 

include stratified analyses on 5–11-year-olds

• For the primary analysis, the number of outcomes observed in a risk interval

after COVID-19 vaccination will be compared to the number expected

‒ Risk interval 0–7 days for myocarditis/pericarditis and seizures

‒ Risk interval 1–21 days for other outcomes

 The expected will be derived from “vaccinated concurrent comparators” who are in 

a comparison interval (days 22-42) after COVID-19 vaccination

 On each day that an outcome occurs, vaccinees who were in their risk interval are

compared with similar vaccinees who were concurrently in their comparison interval

• Comparisons will be adjusted for by single year of age, sex, race/ethnicity, VSD 

site, as well as calendar date

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VSD analytic strategy for the 5–11-year-old age group

 VSD will continue to review medical records and adjudicate any 

potential cases of myocarditis/pericarditis identified within 1–98 days 

following any COVID-19 vaccination

 In addition, VSD will conduct chart review of all identified cases of 

GBS, acute disseminated encephalomyelitis, transverse myelitis, 

anaphylaxis, and cerebral venous sinus thrombosis within 1–98 days 

following any COVID-19 vaccination

 VSD is able to capture information on simultaneous vaccinations

15
16

7 participatingmedical 

research centers with 

vaccine safety experts

CISA

Clinical Immuni

zation 

Safety 

Assessment 

(CISA) Project

†More information about clinical consults available at 

http://www.cdc.gov/vaccinesafety/Activities/CISA.html  Clinical consultservices†  Clinical research
 Clinical case reviews and clinical consults on complex cases of 

vaccine adverse events

 Technical consultation on clinical guidance and clinical 

considerations for use of COVID-19 vaccines*

 Contributions to enhanced surveillance for adverse events

 Clinical research, including in pediatric populations

CISA COVID-19 vaccine core activities

17 * https://www.cdc.gov/vaccines/covid-19/clinical-considerations/covid-19-vaccines-us.html
Veterans

Administration

Centers for 

Medicare and 

Medicaid 

Services

BEST

System

Acumen

Federal

Partners

CBER: Center for Biologics Evaluation and Research

BEST: Biologics Effectiveness and Safety

Blue Health 

Intelligence®

Acumen

IBM

Optum

Columbia 

University 

& OHDSI

RTI RTI

CVS Health

FDA CBER 

Active 

Surveillance 

Program 

IQVIA/

HealthCore

Academic 

Partners

Centers for 

Diseases Control 

and Prevention

Slide courtesy Hui-Lee Wong, PhD, MSc, U.S. FDA 18
Indian Health Service (IHS) vaccine safety monitoring systems

 Passive Surveillance

• Vaccine Adverse Event Reporting System (VAERS)

‒ VAERS Functionality (“IHS” in item #26) permits analysis of AEs in IHS system of care

• IHS Safety Tracking & Response System

‒ Federal and participating tribal sites

‒ Worker-related AEs and vaccine administration errors

 Active Surveillance

• IHS Sentinel Survey

‒ Biweekly survey of AEs, including vaccine administration errors

‒ 58 federal and tribal sites representing IHS Areas

‒ Supports reporting to VAERS

Slide courtesy CAPT Matthew A. Clark, MD, FACP, FAAP, Indian Health Service 19
Department of Defense (DoD)

COVID 19 Vaccine Safety Monitoring Systems and Data Sources

• DoD Vaccine Adverse Event Reporting System (VAERS) data- Spontaneous adverse 

event reporting for DoD population

• Vaccine Adverse Event Clinical System (VAECS) Case tracking and evaluation of 

adverse events following immunizations in the DoD and DoD-affiliated populations

• DoD Electronic Health Record and Defense Medical Surveillance System –Large 

linked electronic health records (AHLTA/MHS GENESIS) and administrative data 

systems for near real-time safety monitoring and research

• Joint Trauma System/COVID 19 Vaccine Breakthrough Metrics- Case tracking of 

COVID-19 infection 14 days or greater following receipt of vaccine

“Medically Ready Force...Ready Medical Force” 20
COVID-19 Vaccine Safety Technical (VaST) Work Group 

 Serve as the central hub for technical subject matter expertise from federal 

agencies conducting post-authorization/approval safety monitoring

 Weekly or biweekly review of data on adverse events of special interest (AESI)

 Shared learning including all members, federal partners, and subject matter 

experts

 Review, evaluate, and interpret post-authorization safety data

 Advise on analyses, interpretation, and data presentation

 Independent discussion of findings by VaST members 

 VaST plans

• Review safety data on 5–11-year-olds as soon as available

• Continue close review of myocarditis data

• Provide updates to the ACIP COVID-19 Vaccines Working Group and ACIP on COVID-19 vaccine safety

21
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 Report adverse events following 

vaccination to VAERS even if you 

aren’t sure if the vaccination 

caused the adverse event

 Enroll yourself in v-safe

 Healthcare providers, encourage 

your patients to enroll in v-safe

 Parents and guardians, you can 

enroll your children in v-safe

What can you do for vaccine safety?

Please get involved, your participation matters

http://vaers.hhs.gov

vsafe.cdc.gov/en/
Acknowledgments

 V-safe Team

 V-safe Pregnancy Registry Team

 VAERS Team

 Clinical Immunization Safety Assessment (CISA) Project

 CDC team investigating long-term effects of myocarditis

 VSD Team, VSD participating sites, and investigators from Kaiser Permanente 

Northern California and the Marshfield Clinic Research Institute

 FDA/Center for Biologics Evaluation and Research

 Indian Health Service 

 U.S. Department of Defense, Defense Health Agency 

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Disclaimer

 The findings and conclusions in this report are those of the authors 

and do not necessarily represent the official position of the Centers 

for Disease Control and Prevention (CDC)

 Mention of a product or company name is for identification 

purposes only and does not constitute endorsement by CDC

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For more information, contact CDC

1-800-CDC-INFO (232-4636)

TTY: 1-888-232-6348 www.cdc.gov

The findings and conclusions in this report are those of the authors and do not necessarily represent the 

official position of the Centers for Disease Control and Prevention.

Thank you!