Eurosurv. Early vaccine effectiveness estimates against medically attended laboratory-confirmed influenza based on influenza surveillance, Beijing, Ch

[tetano]

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

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