COVID-19 Vaccine Safety Technical (VaST) 

Subgroup 

Assessment

Grace M. Lee, MD MPH

Advisory Committee on Immunization Practices

April 14, 2021
COVID-19 Vaccine Safety Technical (VaST) Subgroup

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 Working Group 

and the ACIP on COVID-19 vaccine safety

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VaST Activities

Pre-authorization

Jun-Dec 2020

• 14 meetings to 

prepare for vaccine 

safety surveillance 

in the U.S.

ACIP 

Recommendations

• Dec 12 –

Pfizer/BioNTech

• Dec 14 – 1st dose 

administered in 

U.S.

• Dec 19 – Moderna

• Feb 28 – Janssen

Post-authorization

Dec 21-present

• 16 meetings to 

review vaccine 

safety data across 

multiple 

surveillance 

systems
VaST review of data on cerebral sinus venous 

thrombosis (CSVT) 

 VaST reviewed data on CVST on April 12

 Data from the Vaccine Adverse Event Reporting System 

(VAERS) through April 10, 2021 

–

–

–

3 cases following Moderna vaccine without thrombocytopenia 

(82.6M doses administered)

0 cases following Pfizer-BioNTech vaccine 

(94.7M doses administered)

6 cases following J&J vaccine with thrombocytopenia 

(5.9M doses administered)

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VaST review of data on cerebral sinus venous 

thrombosis (CSVT) 

 Characteristics of cases* 

following J&J vaccine similar to 

those following another COVID19 adenovirus vector vaccine 

reported from Europe

–

–

–

Thrombosis with 

thrombocytopenia 

Elevated D-dimer

Antibodies to platelet factor 4 

(PF4)

5

J&J/Janssen 

(N=6)

AZ 

(N=106)

Age group <50 years <60 years

Gender All female F > M

Race/Ethnicity White, NH TBD

Timing of onset Within 2 

weeks

Within 2 

weeks

*Denominators needed to evaluate risk
Key Issues

 Rare, but serious adverse event

 Risk factors not yet well understood

 Concern for delayed recognition (new entity  CVST with 

thrombocytopenia)

 Need for timely management (IVIG, anticoagulation with nonheparin- based therapies)

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VaST Discussion – 04/12/2021

 Vaccine safety is paramount

– Global safety monitoring efforts and VAERS enabled the CDC and FDA 

to rapidly detect adverse events

 Information about this potential life-threatening adverse 

event should be promptly provided to clinicians to enhance 

early recognition and appropriate treatment of persons who 

develop thrombosis with thrombocytopenia following 

vaccination

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VaST Discussion – 04/12/2021

 Further evaluation of the benefit-risk balance of using 

J&J/Janssen vaccine in specific subgroups is warranted

– Other vaccines are currently available for use in the U.S. 

for prevention of COVID-19 

 Timely and transparent communication with healthcare 

providers and the public is crucial to maintain confidence in 

the vaccination program

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VaST Plans

 Enhanced case identification via public health, clinicians, 

patients, including recent vaccine recipients

– v-safe, VAERS

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Signal 

identification

Signal 

refinement

Signal 

evaluation
VaST Plans

 Signal refinement for CVST with thrombocytopenia

–

–

Review findings in other vaccine safety surveillance systems

Determine risk of developing CVST to inform risk mitigation strategies

 VaST will continue to review all safety data from the U.S. COVID-19 

vaccination program

 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

Martin Kulldorff

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

Susan Hiers

Jared Woo

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