COVID-19 VaST Work Group Report – May 17, 2021

The Advisory Committee on Immunization Practices (ACIP) COVID-19 Vaccine Safety Technical (VaST) Work Group has reviewed post-authorization COVID-19 vaccine safety data on a weekly basis since the start of the U.S. vaccination program. Updates of VaST activities and VaST assessments of safety data were presented at ACIP meetings on January 27, March 1, April 14, April 23, and May 12; ACIP meetings are open to the public.

The VaST session on May 17, 2021, included several presentations on myocarditis following mRNA vaccines, from the Department of Defense (DoD), the Vaccine Adverse Event Reporting System (VAERS), and Vaccine Safety Datalink (VSD). There were also brief updates from the Veteran’s Administration (VA) and the Clinical Immunization Safety Assessment (CISA) groups about their plans for future investigation of myocarditis.

VaST concluded that there are relatively few reports of myocarditis to date and that these cases  seem to occur:

• predominantly in adolescents and young adults,
• more often in males than females,
• more often following dose 2 than dose 1, and
• typically within 4 days after vaccination.

Most cases appear to be mild, and follow-up of cases is ongoing.

Within CDC safety monitoring systems, rates of myocarditis reports in the window following COVID-19 vaccination have not differed from expected baseline rates. However, VaST members felt that information about reports of myocarditis should be communicated to providers.

VaST discussed:

• Further information should be collected through medical record review about potential myocarditis cases that were reported into VAERS.
• Information about this potential adverse event should be provided to clinicians to enhance early recognition and appropriate management of persons who develop myocarditis symptoms following vaccination.
• Collaboration between infectious diseases, cardiology, and rheumatology specialists is needed to provide guidance on diagnosis, treatment, and management of myocarditis.