Updated Monovalent XBB.1.5 COVID-19 Vaccines Effective Against Omicron Subvariants, But Effectiveness Wanes Over Time, Study Finds

MedPage Today (5/29, Kahn) reports, “The updated monovalent XBB.1.5 COVID-19 vaccines were effective against Omicron subvariants circulating during the most recent respiratory virus season, but their effectiveness waned over time, according to a brief report.” The three vaccines developed by Moderna, Pfizer-BioNTech and Novavax “were 66.8% effective against hospitalization at 4 weeks, decreasing to 57.1% after 10 weeks, wrote” researchers in the New England Journal of Medicine. Additionally, “data appeared to point to lower effectiveness against infection, hospitalization, and death after the arrival of the JN.1 subvariant, the dominant strain in the U.S. through the end of March of this year.”