Safety Monitoring of COVID-19 Vaccine Booster Doses Among Adults — United States, September 22, 2021–February 6, 2022

approximately 82.6 million U.S. residents aged 18 years received a COVID-19 vaccine booster dose.* The Food and Drug Administration (FDA) has authorized a booster dose of either the same product administered for the primary series (homologous) or a booster dose that differs from the product administered for the primary series (heterologous). These booster authorizations apply to all three COVID-19 vaccines used in the United States (1-3). The Advisory Committee on Immunization Practices (ACIP) recommended preferential use of an mRNA COVID-19 vaccine (mRNA-1273 Moderna or BNT162b2 Pfizer-BioNTech) for a booster, even for persons who received the Ad26.COV2.S (Janssen Johnson & Johnson) COVID-19 vaccine for their single-dose primary series. To characterize the safety of COVID-19 vaccine boosters among persons aged 18 years during September 22, 2021-February 6, 2022, CDC reviewed adverse events and health impact assessments following receipt of a booster that were reported to v-safe, a voluntary smartphone-based safety surveillance system for adverse events after COVID-19 vaccination, and adverse events reported to the Vaccine Adverse Event Reporting System (VAERS), a passive vaccine safety surveillance system managed by CDC and FDA. Among 721,562 v-safe registrants aged 18 years who reported receiving a booster, 88.8% received homologous COVID-19 mRNA vaccination. Among registrants who reported a homologous COVID-19 mRNA booster dose, systemic reactions were less frequent following the booster (58.4% Pfizer-BioNTech and 64.4% Moderna, respectively) than were those following dose 2 (66.7% and 78.4%, respectively). The adjusted odds of reporting a systemic reaction were higher following a Moderna COVID-19 vaccine booster, irrespective of the vaccine received * https://covid.cdc.gov/covid-data-tracker/#vaccination-demographic The FDA has authorized a booster dose of either the same product administered for the primary series (homologous) or a booster dose that differs from the product administered for the primary series (heterologous). These booster authorizations apply to all three COVID-19 vaccines used in the United States: 1) Pfizer-BioNTech COVID-19 vaccine 5 months after dose 2 for persons aged 12 years, 2) Moderna COVID-19 vaccine 5 months after dose 2 for persons aged 18 years, and 3) Janssen COVID-19 vaccine 2 months after a single dose for persons aged 18 years. https://www.cdc.gov/vaccines/covid-19/clinical-considerations/covid-19vaccines-us.html