COVID-19 Incidence and Mortality Among Unvaccinated and Vaccinated Persons Aged ≥12 Years by Receipt of Bivalent Booster Doses and Time Since Vaccination — 24 U.S. Jurisdictions, October 3, 2021–December 24, 2022

What is already known about this topic?

COVID-19 vaccine effectiveness decreased with waning of vaccine-derived immunity and emerging Omicron sublineages. An updated (bivalent) booster dose enhances protection against infection and medically attended illness, but protection against death has not been evaluated.

What is added by this report?

Bivalent booster recipients in 24 U.S. jurisdictions had slightly higher protection against infection and significantly higher protection against death than was observed for monovalent booster recipients or unvaccinated persons, especially among older adults.

What are the implications for public health practice?

Bivalent COVID-19 booster doses protected against infection and death during BA.4/BA.5 circulation. All eligible persons should get 1 bivalent booster dose ≥2 months after their COVID-19 primary series or last monovalent booster dose.