THURSDAY, Sept. 30, 2021 (HealthDay News) -- Safety monitoring indicates that the pattern of adverse reactions after dose 3 of the COVID-19 vaccine is similar to that seen after dose 2, according to research published in the Oct. 1 issue of the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.
Anne M. Hause, Ph.D., from the CDC COVID-19 Response Team, and colleagues collected information on adverse events from 22,191 v-safe registrants reporting receipt of an additional dose of COVID-19 vaccine during Aug.12 to Sept. 19, 2021.
The registrants mainly reported a primary two-dose mRNA vaccination series (97.6 percent), which was followed by a third dose of the same vaccine. The researchers found that of the 12,591 individuals who completed a health check-in survey for all three doses, 79.4 and 74.1 percent reported local or systemic reactions, respectively, compared with 77.6 and 76.5 percent after dose 2.
"Initial analyses of safety data from >22,000 v-safe registrants shows that local reactions are slightly increased and systemic reactions are slightly decreased after dose three of an mRNA than after dose two," the authors write. "No unexpected patterns of adverse reactions were identified; those reported were mild to moderate and transient. CDC will continue to monitor the safety of additional doses of COVID-19 vaccine."