The 2024-25 COVID mRNA vaccines targeting JN.1 were highly effective in protecting against hospitalization and death for at least 4 months in a cohort of Danish citizens aged 65 and older by October 1, 2024. The new analysis estimating the vaccine efficacy (VE) of last season’s COVID vaccines was published earlier this week in The Lancet Infectious Diseases.

In total, 894,560 Danish residents were included in the study, with a median age of 76. By Jan 31, 2025, 820,229 (91.7%) of the participants had received a JN.1 vaccine. Among those without updated JN.1 vaccination (74,331), 278 COVID-19 hospitalizations and 84 deaths were observed during 25.6 million person-days.

In contrast 197 COVID-19 hospitalizations and 56 deaths in 62.9 million person-days were observed in residents who received Pfizer’s Comirnaty (among 728,868 recipients). And 10 COVID-19 hospitalizations and 1 death were observed during 9.2 million person-days in those vaccinated with Moderna’s Spikevax vaccine (91,461 recipients).