COVID-19 Vaccine Safety Technical (VaST) 

Work Group 

Safety Assessment 

H. Keipp Talbot, MD MPH (VaST Chair)

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

Advisory Committee on Immunization Practices

December 16, 2021
COVID-19 Vaccine Safety Technical (VaST) Work Group

Objectives

 Review, evaluate, and interpret post-authorization/approval COVID-19 

vaccination 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 presentation of vaccine safety data

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

ACIP on COVID-19 vaccine safety

VaST meetings 

 December 21, 2020 – present: 45 meetings to review vaccine safety data

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VaST meeting - April 12, 2021

First review of Central Venous Sinus Thrombosis 

(CVST) with thrombocytopenia

 6 cases of CVST with thrombocytopenia identified as rare but 

serious adverse event following Janssen COVID-19 vaccine

 Risk factors for CVST with thrombocytopenia not well understood

 Timely and transparent communication with healthcare providers 

and the public is crucial to maintain confidence in the COVID-19 

vaccination program

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HAN Communication 

April 13, 2021
ACIP meetings – April 14 and 23, 2021

April 14

 Reviewed cases of CVST with thrombocytopenia after COVID-19 vaccination 

 Discussed need for additional information to support evidence-based 

decision making, including

– Age and gender-specific risk estimates

– Evaluation of the benefit-risk balance of using Janssen vaccine in specific 

subgroups

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ACIP meetings – April 14 and 23, 2021 

April 23 

 Risk of TTS appears to be highest in females <50 years

– 15 cases reported; rare but serious condition

– Other risk factors for TTS not well established yet

 Risk mitigation strategies 

– Minimize exposure in high-risk populations 

– Increase awareness & ensure timely diagnosis and management of TTS

– Educate patients about benefits and risks of available vaccines

 VaST will continue to monitor TTS, other thromboembolic disease, and 

thrombocytopenia in all available vaccine safety surveillance systems

 VaST will update the ACIP COVID-19 vaccines workgroup, ACIP secretariat and 

ACIP on a regular basis

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Ongoing VaST review of TTS and Janssen COVID-19 

vaccination, May through December 2021

 VaST meetings

– Regular updates on TTS data from VAERS, VSD and other safety systems

 VaST assessments of Janssen J&J COVID-19 vaccination safety 

represented to ACIP*

– May 12 (focus on TTS) and July 22 (focus on GBS)

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TTS, thrombosis with thrombocytopenia syndrome; GBS, Guillain-Barré syndrome

*https://www.cdc.gov/vaccines/acip/work-groups-vast/index.html
VaST assessment – December 6, 2021

 Through August 2021, 54 TTS cases and 9 deaths reported following Janssen 

COVID-19 vaccination in the United States

 The TTS case reporting rate following Janssen COVID 19 vaccination is higher 

than previous estimates in men as well as women, and in wider age range 

 Follow-up investigations have provided more evidence for relationship between 

Janssen COVID-19 vaccination and TTS and associated severe outcomes

 VaST recognizes the public health benefits of the Janssen COVID-19 vaccine; 

however, the additional TTS cases and reported deaths are concerning

 VaST felt that the new data on TTS risk need to be put into context of a benefitrisk assessment, and should be presented to the ACIP COVID-19 Vaccines Work 

Group and to ACIP

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VaST Members

VaST Members

Keipp Talbot (ACIP)

Robert Hopkins (NVAC)

Matt Daley

Grace Lee

Veronica McNally

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)

Valerie Marshall (OIDP)

Jeffrey Kelman (CMS)

Matthew Clark (IHS)

Mary Rubin (HRSA)

Fran Cunningham (VA)

Limone Collins (DoD)

Administrative Support

Jared Woo

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