Eurosurv. Early vaccine effectiveness estimates against medically attended laboratory-confirmed influenza based on influenza surveillance, Beijing, China, 2024/25 season

[tetano]

• Ying Sun^1,2,3 , Weixian Shi^1,2 , Daitao Zhang^1,2,3 , Chunna Ma^1,2 , Zhaomin Feng^1,2,3 , Jiaojiao Zhang^1,2 , Dan Wu^1,2 , Li Zhang^1,2 , Jia Li^1,2 , Wei Duan^1,2 , Yingying Wang^1,2 , Jiaxin Ma^1,2 , Lu Zhang^1,2 , Xiaodi Hu^1,2 , Peng Yang^1,2,3 , Quanyi Wang^1,2,3

We estimated early influenza vaccine effectiveness (VE) for the 2024/25 season in outpatients, in Beijing using a test-negative design. A(H1N1)pdm09 dominated (99.3%), all sequenced strains (n = 38) clustered in clade 6B.1A.5a.2a, and 37 of 38 antigenically similar to the vaccine strain. VE against any influenza virus infection was 48.5% (95% CI: 34.8–59.5) and 48.7% (95% CI: 35.1–59.7) against A(H1N1)pdm09. Vaccination in the current or previous season against any influenza showed a VE of 52.5% to 54.9%, compared to no vaccination in both seasons.

https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2025.30.7.2500084