Top 5 Takeaways:

  1. Safety Profile Similar to Monovalent Boosters: Early safety findings for bivalent COVID-19 mRNA booster doses in persons aged ≥12 years are consistent with those reported for monovalent boosters.
  2. High Rate of Nonserious Adverse Events: Among the 22.6 million bivalent booster doses administered, 95.5% of VAERS reports were nonserious.
  3. Most Common Adverse Events: Injection site reactions and systemic (fatigue, fever, headache, etc.) symptoms were the most frequently reported side effects in the first week after vaccination.
  4. Low Rate of Serious Adverse Events: Serious adverse events were rare, accounting for only 4.5% of VAERS reports.
  5. COVID-19 Illness More Severe Than Vaccine Side Effects: Health impacts after COVID-19 vaccination are less frequent and less severe compared to those associated with COVID-19 illness.

Original Article Author and Citation

Corresponding Author

Anne M. Hause,

Suggested Citation

Hause AM, Marquez P, Zhang B, et al. Safety Monitoring of Bivalent COVID-19 mRNA Vaccine Booster Doses Among Persons Aged ≥12 Years — United States, August 31–October 23, 2022. MMWR Morb Mortal Wkly Rep 2022;71:1401–1406. DOI: .


The CDC conducted a safety monitoring study of bivalent COVID-19 mRNA vaccine booster doses in individuals aged ≥12 years. This study covered the period from August 31 to October 23, 2022, during which approximately 22.6 million doses were administered.


The study utilized data from v-safe, a smartphone-based safety surveillance system, and VAERS, a passive vaccine safety surveillance system. It analyzed adverse events and health impacts reported following the administration of Pfizer-BioNTech and Moderna bivalent booster doses.


The study found that the adverse events after bivalent booster vaccination were generally similar to those reported after monovalent booster doses. Local and systemic reactions were common, but severe adverse events like myocarditis were rare. Reporting rates of myocarditis were similar to or lower than those after primary series doses. The study also noted that COVID-19 vaccination reduced the severity of COVID-19 disease, including the risk of hospitalization and death.


Overall, the study concludes that the bivalent COVID-19 mRNA booster doses have a safety profile comparable to monovalent boosters. The reported adverse events are consistent with those previously observed, and the health impacts are less severe than those associated with COVID-19 illness.

The study encourages healthcare providers and patients to continue with the vaccination program, highlighting the safety and benefits of the bivalent boosters in preventing severe COVID-19 complications. CDC and FDA will continue to monitor vaccine safety and update recommendations as needed.

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