COVID-19 Vaccine Safety Technical (VaST) 

Work Group 

Assessment

Grace M. Lee, MD, MPH (ACIP Chair)

Robert H. Hopkins, Jr., MD (NVAC Chair)

Advisory Committee on Immunization Practices

June 23, 2021
start of 

vaccination

active surveillance, passive 

surveillance, case consults

Vaccine Safety Surveillance in the U.S.

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COVID-19 Vaccine Safety Technical (VaST) Work Group

Objectives

▪ Review, evaluate, and interpret post-authorization/approval 

COVID-19 vaccine safety data

▪ Serve as the central hub for technical subject matter expertise 

from federal agencies conducting post-authorization/approval 

safety monitoring

▪ Advise on analyses, interpretation, and data presentation

▪ Provide updates to the ACIP COVID-19 Vaccines Work Group and 

the ACIP on COVID-19 vaccine safety

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VaST Activities

Dec 21, 2020 – present:

• 25 independent meetings to review vaccine safety data

• 5 joint meetings with COVID-19 Vaccines Work Group focused on safety

Dec Jan Feb Mar Apr May Jun

Dec 12 

Pfizer

(16+)

Feb 28 

Janssen 

(18+)

Apr 14 

CVST 

following 

Janssen

Dec 19 

Moderna 

(18+)

Apr 23 

TTS 

updates; 

Janssen 

resumed 

with 

warning

May 12 

Pfizer

(12-15)

Jan 27

Anaphylaxis 

following 

mRNA 

vaccines

Mar 1

Anaphylaxis 

updates;

Pregnancy 

vaccine 

safety data

May 12

TTS 

updates

Jun 23

Myocarditis 

updates

May 17 & 24

Myocarditis

ACIP votes 

following 

EUA

VaST 

assessments 

at ACIP 

meetings or 

website

CVST, cerebral venous sinus thrombosis; TTS, thrombosis with thrombocytopenia syndrome 4
VaST Work Group Report – May 17

▪ Relatively few reports of myocarditis to date occurring:

– predominantly in adolescents and young adults, 

– more often in males than females,

– more often following dose 2 than dose 1

– typically, within one week after vaccination

▪ Majority of patients appear to have transient symptoms, rapid resolution 

of laboratory abnormalities, and brief hospitalizations

▪ Long term follow-up data are limited

https://www.cdc.gov/vaccines/acip/work-groups-vast/index.html 5
VaST Work Group Report – May 24

▪ Higher number of observed vs. expected myocarditis/pericarditis cases in 16–24-

year-olds following dose 2 of mRNA vaccines in VAERS using a 30-day window

▪ VaST members discussed need for: 

– Continued vaccine safety monitoring through multiple surveillance systems as 

vaccination rates increase in younger age groups

– Multi-disciplinary collaboration to provide clinical guidance about early 

recognition, differential diagnosis, diagnostic testing, and appropriate 

management of persons who develop myocarditis or pericarditis

– Long-term follow up of patients to understand clinical course and resolution 

following both COVID-19 infection and COVID-19 vaccination

https://www.cdc.gov/vaccines/acip/work-groups-vast/index.html 6
https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/myocarditis.html 7
https://www.cdc.gov/vaccines/covid-19/clinical-considerations/covid-19-vaccines-us.html 8
VaST Discussion and Interpretation Regarding 

Adolescent Vaccination

▪ v-safe data indicate comparable local and systemic reactogenicity rates 

among 12–15-year-olds and 16–25-year-olds

▪ Dizziness and syncope are the most common adverse events reported 

among 12–15-year-olds in VAERS

▪ Partnerships and ongoing communication with clinician communities have 

enhanced vaccine safety efforts through early recognition of potential 

adverse events, such as myocarditis 

Marshall et al., Pediatrics 2021 9
VaST Discussion and Interpretation

▪ Risk of myocarditis/pericarditis following mRNA vaccination in adolescents 

and young adults aged 12-39 years is notably higher after dose 2 and in males

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All (chart 

confirmed 

in VSD)

Females 

(ICD10 in 

VSD)

Females 

(crude in 

VAERS)

Males 

(ICD10 in 

VSD)

Males 

(crude in 

VAERS)

Dose 1 4.4 1.9 0.8 - 1.5 4.7 2.0 - 9.8

Dose 2 12.6 4.7 1.8 - 9.1 32.0 10.0 - 66.7

Myocarditis/pericarditis per million doses administered in VSD and VAERS

Data using 21-day window (VSD), no restriction (VAERS)
VaST Discussion and Interpretation

▪ Data available to date suggest likely association of myocarditis 

with mRNA vaccination in adolescents and young adults

▪ Clinical presentation of myocarditis cases following 

vaccination has been distinct, occurring most often within one 

week after dose 2, with chest pain as the most common 

presentation 

▪ Further data are being compiled to understand potential risk 

factors, optimal management strategies, and long-term 

outcomes

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VaST will continue to

▪ Review data on myocarditis/pericarditis from available 

surveillance systems and ongoing safety evaluations 

▪ Review and assess all safety data from surveillance systems 

and ongoing safety evaluations

▪ Update the ACIP COVID-19 Vaccines Workgroup, ACIP 

secretariat and ACIP on a regular basis

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VaST Members

VaST Members

Grace Lee (ACIP)

Robert Hopkins (NVAC)

Matt Daley

Veronica McNally

Keipp Talbot

Kathy Edwards

Lisa Jackson

Jennifer Nelson

Laura Riley

Robert Schechter

Patricia Whitley-Williams

CDC Co-Leads

Lauri Markowitz

Melinda Wharton

Ex Officio and Liaison Representatives 

Tatiana Beresnev (NIH)

Karen Farizo; Hui Lee Wong (FDA)

Judith Steinberg (OIDP)

Jeffrey Kelman (CMS)

Matthew Clark (IHS)

Mary Rubin (HRSA)

Fran Cunningham (VA)

Limone Collins (DoD)

Administrative Support

Jared Woo

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