CDC reports on allergic reactions to Moderna COVID-19 vaccine

The Centers for Disease Control and Prevention today reported 10 cases of anaphylaxis, a life-threatening allergic reaction, among the more than 4 million people who received a first dose of the Moderna COVID-19 vaccine between Dec. 21, 2020, and Jan. 10, 2021.

That’s an estimated 2.5 cases per 1 million doses. Nine cases occurred within 15 minutes of vaccination and one after 30 minutes.

All of the individuals received emergency treatment with epinephrine; four were treated in an emergency department and six were hospitalized. All eight for whom follow-up information was available reportedly recovered.

CDC Jan. 6 reported 21 cases of anaphylaxis among the nearly 1.9 million people who received a first dose of the Pfizer COVID-19 vaccine between Dec. 14 and 23. That’s an estimated 11.1 cases per 1 million doses, but still a rare outcome, according to Nancy Messonnier, M.D., director of CDC’s National Center for Immunization and Respiratory Diseases.

CDC recommends that locations administering COVID-19 vaccines adhere to its guidance, including screening recipients for contraindications and precautions, implementing recommended post-vaccination observation periods and immediately treating suspected anaphylaxis with intramuscular epinephrine injection.