JAMA Netw Open

Last season's COVID-19 vaccines effective in reducing hospitalizations, severe outcomes

February 4, 2026

This multicenter test-negative case-control study evaluated adults hospitalized with COVID‑19–like illness across 26 U.S. hospitals from September 2024 to April 2025. Among 8,493 participants, vaccine effectiveness (VE) against COVID‑19–associated hospitalization was 40% (95% confidence interval [CI], 27%–51%), with sustained protection through 90 to 179 days after vaccination. VE was higher (79% [95% CI, 55%–92%]) against the most severe outcome of invasive mechanical ventilation or death. VE varied by lineage—49% (KP.3.1.1), 34% (XEC), and 24% (LP.8.1)—corresponding with increasing median time since vaccination. Estimates were similar for lineages carrying spike mutations associated with immune evasion.

Clinical takeaway: Consider discussing updated COVID‑19 vaccination with patients, particularly those at higher risk for severe disease.

Source:

Ma KC, et al; Investigating Respiratory Viruses in the Acutely Ill (IVY) Network. (2026, February 2). JAMA Netw Open. Estimated Effectiveness of 2024-2025 COVID-19 Vaccination Against Severe COVID-19. https://pubmed.ncbi.nlm.nih.gov/41632473/