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  • Review Examines Safety of COVID-19 Vaccine in Adolescents

    August 19, 2021, 12:18 p.m. News Staff — For family physicians and other clinicians who have faced questions from parents about the safety of the COVID-19 vaccine in adolescents, recent study results from the CDC should provide some much-needed answers.

    physician with young patient

    The study, posted as a Morbidity and Mortality Weekly Report Early Release July 30 and then published in MMWR Aug. 6, analyzed safety data from two different vaccine safety surveillance systems. The results indicated that administration of the Pfizer-BioNTech COVID-19 vaccine in adolescents aged 12-17 years produced reactions consistent with those reported in preauthorization clinical trials. The study also found that while adverse events occurred in roughly one out of every 1,000 patients vaccinated, the majority of those events were considered not serious.

    Background and Methods

    The FDA issued an emergency use authorization for the Pfizer-BioNTech vaccine for use in people aged 16 and older on Dec. 11, 2020. The agency expanded the EUA  on May 10, 2021, to include adolescents aged 12-15 years. A month later, the FDA revised the vaccine’s patient and provider fact sheets to include additional information regarding a suggested increased risk of myocarditis and pericarditis following vaccination.

    In the MMWR study, researchers analyzed data from the Vaccine Adverse Event Reporting System, which is comanaged by the CDC and FDA, and v-safe, a voluntary smartphone-based system developed by the CDC in response to the pandemic.

    The analysis reviewed VAERS and v-safe data on U.S. adolescents aged 12-17 years who received the Pfizer-BioNTech COVID-19 vaccine between Dec. 14, 2020 and July 16, 2021, with the caveat that VAERS reports for adolescents aged 12-15 were excluded if vaccination occurred before the May 10, 2021, EUA expansion date. Data was assessed by sex, age group and race/ethnicity. About 8.9 million adolescents in the United States received the Pfizer-BioNTech vaccine during this period.

    Story Highlights

    VAERS Data

    VAERS received 9,246 reports of adverse events in this population of adolescents during the study period. The majority (58.1%) occurred in those aged 12-15, with the remainder occurring in 16- and 17-year-olds.

    Of the adverse events reported, almost 91% were for nonserious events. The most common nonserious events were dizziness, syncope and nausea.

    Of the serious adverse events that occurred, the most common conditions reported were chest pain, increased troponin levels and myocarditis.

    The CDC also reviewed 14 reports of death after vaccination, which equated to roughly one death for every 635,000 adolescents who received the vaccine. All reports were reviewed by CDC physicians. Four deaths occurred in individuals aged 12-15 and the remainder occurred in 16- and 17-year-olds. A total of six deaths were attributed to pulmonary embolism, suicide or intracranial hemorrhage; the causes of death in six other cases were listed as unknown or pending further records at the time the study was published.

    It should be noted that according to the CDC’s COVID Data Tracker,  as of Aug. 18, 225 deaths from COVID-19 infection have occurred in individuals 12 to 17 years of age.

    It should also be noted that according to the MMWR study, no reports of death to VAERS were determined to be the result of myocarditis. As of June 11, VAERS had reported 1,226 cases of myocarditis or pericarditis occurring following COVID-19 vaccination, with most cases occurring in adolescent males and young adults 16 and older.  

    On June 23, the CDC’s Advisory Committee on Immunization Practices reviewed the available data and concluded that while an elevated risk for myocarditis had been observed, the benefits of COVID-19 vaccination outweighed the risks of myocarditis, and the ACIP recommended continued use of the vaccine in individuals 12 years and older. In response, the FDA revised the fact sheets for clinicians and patients to reflect the suggested risk of these conditions following COVID-19 vaccination.

    V-safe Data

    More than 129,000 adolescents who received the Pfizer-BioNTech vaccine enrolled in the v-safe program during the study period.

    For each dose and age group, reactions were reported most frequently the day after vaccination. For all adolescents, the most frequently reported reactions after receiving either dose of the vaccine were pain at the site of injection, fatigue and headache.

    Among patients who completed at least one v-safe health check-in survey within a week of vaccination, 25.4% of those aged 12-15 and 28.6% of those aged 16-17 experienced a health impact after the second dose; 23.1% of the younger group and 24.7% of the older group reported that they were unable to perform normal activities the day after receiving the second dose. Less than 1% of all adolescents required medical care in the week after receipt of either dose, and 56 individuals required hospitalization.

    Study Limits and Conclusions

    The MMWR study authors noted several limits to their findings, including

    • possible underreporting and reporting biases;
    • unavailability of medical records, death certificates and autopsy reports, which could delay medical reviews of reported deaths;
    • the fact that lack of a statistical safety signal in planned monitoring does not preclude a safety concern;
    • the possibility that some cases of myocarditis were not included; and
    • the possibility that v-safe data may not be generalizable to the vaccinated adolescent population.

    Given these limitations, the study authors concluded that the initial safety findings of the Pfizer-BioNTech vaccine were similar to those described in clinical trials, with the exception of myocarditis (which was observed after vaccination in postauthorization monitoring).

    The authors added that the CDC and FDA will continue to monitor for adverse events following COVID-19 vaccination, and will share data with the ACIP to help determine risk/benefit assessments for all COVID-19 vaccines.