May 20, 2021

Thrombocytopenia Including Immune Thrombocytopenia after Receipt of MRNA COVID-19 Vaccines Reported to the Vaccine Adverse Event Reporting System (VAERS)

Category: Article Summary

Topic: Vaccines and Immunity

Keywords (Tags): adverse effects, immunity, vaccines

• An analysis of reported adverse events following vaccination with an mRNA COVID-19 vaccine indicates that the reported number of thrombocytopenia cases does not suggest a safety concern attributable to mRNA COVID-19 vaccines at this time. Fifteen cases of thrombocytopenia were identified among 18,841,309 doses of Pfizer-BioNTech vaccine and 13 cases among 16,260,102 doses of Moderna vaccine according to an analysis by the FDA of the Vaccine Adverse Event Reporting System (VAERS) up to February 4, 2021, corresponding to a reporting rate of 0.8 per million doses for both vaccines. By contrast, the annual incidence of immune thrombocytopenia, which is included in some of the observed cases, is 3.3 per 100,000 adults.

Welsh et al. (Apr 30, 2021). Thrombocytopenia Including Immune Thrombocytopenia after Receipt of MRNA COVID-19 Vaccines Reported to the Vaccine Adverse Event Reporting System (VAERS). Vaccine. https://doi.org/10.1016/j.vaccine.2021.04.054