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
Amelia G. Johnson, Lauren Linde, Akilah R. Ali, Allison DeSantis, Minchan Shi, Carolyn Adam, Brandy Armstrong, Brett Armstrong, Madison Asbell, Steven Auche, Nagla S. Bayoumi, Boudu Bingay, Melisse Chasse, Scott Christofferson, Maaike Cima, Kevin Cueto, Spencer Cunningham, Janelle Delgadillo, Vajeera Dorabawila, Cherie Drenzek, Brandi Dupervil, Tonji Durant, Aaron T. Fleischauer, Ross Hamilton, Pauline Harrington, Liam Hicks, Jeffrey D. Hodis, Dina Hoefer, Sam Horrocks, Mikhail Hoskins, Sofia Husain, L. Amanda Ingram, Amanda Jara, Amanda Jones, FNU Kanishka, Ramandeep Kaur, Saadiah I. Khan, Samantha Kirkendall, Priscilla Lauro, Shelby Lyons, Joshua Mansfield, Amanda Markelz, John Masarik, Donald B. McCormick, Erica Mendoza, Keeley J. Morris, Enaholo Omoike, Komal Patel, Melissa Pike, Tamara Pilishvili, Kevin Praetorius, Isaiah G. Reed, Rachel Severson, Nekabari Sigalo, Emma Stanislawski, Sarah Stich, Buddhi Tilakaratne, Kathryn Turner, Caleb Wiedeman, Allison Zaldivar, Benjamin J. Silk, Heather M. Scobie
Abstract
During the late BA.4/BA.5 period, unvaccinated persons had higher COVID-19 mortality and infection rates than persons receiving bivalent doses (mortality RR = 14.1 and infection RR = 2.8) and to a lesser extent persons vaccinated with only monovalent doses (mortality RR = 5.4 and infection RR = 2.5). Among older adults, mortality rates among unvaccinated persons were significantly higher than among those who had received a bivalent booster (65-79 years; RR = 23.7 and ≥80 years; 10.3) or a monovalent booster (65-79 years; 8.3 and ≥80 years; 4.2). In a second analysis stratified by time since booster vaccination, there was a progressive decline from the Delta period (RR = 50.7) to the early BA.4/BA.5 period (7.4) in relative COVID-19 mortality rates among unvaccinated persons compared with persons receiving who had received a monovalent booster within 2 weeks-2 months. During the early BA.4/BA.5 period, declines in relative mortality rates were observed at 6-8 (RR = 4.6), 9-11 (4.5), and ≥12 (2.5) months after receiving a monovalent booster. In contrast, bivalent boosters received during the preceding 2 weeks-2 months improved protection against death (RR = 15.2) during the late BA.4/BA.5 period. In both analyses, when compared with unvaccinated persons, persons who had received bivalent boosters were provided additional protection against death over monovalent doses or monovalent boosters. Restored protection was highest in older adults. All persons should stay up to date with COVID-19 vaccination, including receipt of a bivalent booster by eligible persons, to reduce the risk for severe COVID-19.