For U.S. Teens, Most Adverse Events to COVID-19 Vaccine Nonserious

For U.S. adolescents aged 12 to 17 years receiving Pfizer-BioNTech COVID-19 vaccination, most adverse events are nonserious, according to research published in the July 30 early-release 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 further characterized the safety of the Pfizer-BioNTech vaccine by reviewing adverse events reported to the Vaccine Adverse Event Reporting System and adverse events and health impact assessments reported in v-safe (a smartphone-based surveillance system) after receipt of the vaccine for U.S. adolescents aged 12 to 17 years from Dec. 14, 2020, to July 16, 2021.

About 8.9 million U.S. adolescents aged 12 to 17 years had received the Pfizer-BioNTech vaccine as of July 16, 2021. The researchers found that the Vaccine Adverse Event Reporting System received 9,246 reports after Pfizer-BioNTech vaccination among 12- to 17-year-olds: 90.7 percent were for nonserious adverse events and 9.3 percent were for serious adverse events, including 4.3 percent for myocarditis. Local and systemic reactions were reported with a frequency similar to that reported in preauthorization clinical trials among about 129,000 U.S. adolescents enrolled in v-safe (63.4 and 48.9 percent, respectively). Systemic reactions occurred more often after the second dose.

"The initial safety findings of Pfizer-BioNTech vaccine administered to U.S. adolescents aged 12 to 17 years are similar to those described in the clinical trials, with the exception of myocarditis, a rare serious adverse event associated with receipt of mRNA-based COVID-19 vaccines; follow-up of reported myocarditis cases is ongoing," the authors write.