Updated COVID-19 vaccine has effectiveness of 54 percent, according to new research

Updated monovalent COVID-19 vaccines offer vaccine effectiveness (VE) of 54 percent against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, according to research published in the Feb. 1 issue of the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.

Ruth Link-Gelles, Ph.D., from the CDC in Atlanta, and colleagues analyzed data from the Increasing Community Access to Testing SARS-CoV-2 pharmacy testing program to estimate updated 2023 to 2024 COVID-19 VE against symptomatic SARS-CoV-2 infection with a monovalent XBB.1.5-derived vaccine.

The researchers found that overall VE among adults aged 18 years and older was 54 percent at a median of 52 days after vaccination among 9,222 total eligible tests. VE at 60 to 119 days after vaccination was 49 percent among tests exhibiting spike gene target failure (SGTF) and 60 percent among tests without SGTF in a total of 2,199 tests performed at a laboratory with SGTF testing.

"Vaccination provided protection for infections caused by JN.1 and infections caused by XBB-related lineages. Waning of effectiveness is expected with additional elapsed time since vaccination, especially against less severe disease," the authors write. "All persons aged ≥6 months should stay up to date with COVID-19 vaccination, including receiving a dose of updated vaccine."