Bivalent COVID-19 booster safety profile consistent with monovalent vaccine

Safety findings for the bivalent COVID-19 booster vaccine are similar to those from the monovalent vaccine in children aged 5 to 11 years, according to the Centers for Disease Control and Prevention (CDC).

The bivalent vaccination was given Emergency Use Authorization in children aged 5 to 11 years by the US Food and Drug Administration (FDA) on October 12, 2022. On December 8, 2022, this was extended to children aged 6 months and older.

From October 12, 2022, to January 1, 2023, 861,251 children aged 5 to 11 years received a bivalent Pfizer booster, and 92,108 children aged 6 to 11 years received a bivalent Moderna booster.

The CDC established a surveillance system to observe adverse reactions to the bivalent vaccine. This includes v-safe, a smartphone surveillance system, and the Vaccine Adverse Event Reporting System (VAERS), a passive vaccine safety surveillance system co-managed by the CDC and FDA.

About 69% of children who received a bivalent vaccine reported local reactions, and about 50% reported systemic reactions. Of these, 99.8% of reactions reported to VAERS were not severe. Reported reactions were in line with those reported from monovalent vaccinations. Myocarditis and death were not reported in any cases.

For v-safe data, local reactions were reported by about 66% of children who received their booster from Pfizer, and about 77% of children who received their booster from Moderna. Systemic reactions were reported by about 46% of children who received a Pfizer booster and about 62% of children who received a Moderna booster.

The most common adverse reactions reported were injection site pain in about 66% of patients, fatigue in 33%, and headache in about 23%. Most reactions were mild and mostly appeared in the day following vaccination, with the prevalence of reactions decreasing in the following days.

About 14% of children could not attend school at least 1 day in the week after vaccination, about 14% couldn’t complete daily activities, and about 2% had parents or caregivers seek medical care for their children. Medical care was most common at an outpatient clinic, and no case required hospital care.

Vaccination errors were the most common event reported to VAERS, making up about 84% of reports. These included incorrect dose administered, incorrect product formulation administered, product preparation issue, and product administered to a patient of an inappropriate age.

Of over 950,000 doses of the bivalent booster vaccine given to children aged 5 to 11 years, only 2 reports have been made to VAERS of serious adverse reactions. These findings are consistent with those of the monovalent booster, and the Advisory Committee on Immunization Practices recommends children aged 6 months and older receive a bivalent booster vaccine if available.

Reference

Hause AM, Marquez P, Zhang B, Su JR, Myers TR, Gee J, et al. Safety Monitoring of Bivalent COVID-19 mRNA Vaccine Booster Doses Among Children Aged 5–11 Years — United States, October 12–January 1, 2023. MMWR Morb Mortal Wkly Rep. 2023;72:39–43. doi:10.15585/mmwr.mm7202a5