Effectiveness of 2025 bi-annual COVID-19 vaccination campaigns against hospitalisation in England

Background In 2025, COVID-19 vaccination programmes in England targeted adults aged [≥]75 years and immunosuppressed individuals, with JN.1-based vaccines offered in spring and KP.2-based vaccines offered in autumn. This study evaluated vaccine effectiveness (VE) against COVID-19 hospitalisation following these campaigns and assessed VE in immunosuppressed populations. Methods VE against COVID-19 hospitalisation in adults aged [≥]75 years following the 2025 spring JN.1 and autumn KP.2 vaccination campaigns was estimated using a test-negative case-control design. Logistic regression was used to calculate VE among eligible hospitalised individuals, adjusting for covariates. Manufacturer-specific analyses were performed for the spring 2025 campaign. VE in immunosuppressed and non-immunosuppressed adults aged [≥]75 years was assessed by pooling estimates from the autumn 2024 and spring and autumn 2025 campaigns using fixed-effects meta-analysis. Results Spring 2025 JN.1 vaccines conferred moderate protection, peaking at 55% (95%CI: 45-62%) within 5-9 weeks and declining to 17% (95%CI: -18-42%) from 35 weeks onwards. Autumn 2025 KP.2 VE peaked at 48% (95%CI: 34-59%) at 5-9 weeks, with follow-up needed to assess long-term protection. No significant differences were observed between manufacturers in the spring campaign. VE following autumn KP.2 vaccination was lower among individuals who received a spring JN.1 vaccine. When assessed across three campaigns, there was some evidence that VE was lower in individuals with immunosuppression than those without. Conclusion The 2025 COVID-19 vaccination programmes in England provided moderate protection against COVID-19 hospitalisation in adults aged [≥]75 years, with protection waning over time. The findings support the continued benefit of seasonal vaccination in high-risk groups, including immunosuppressed individuals.