2025 Yes https://doi.org/10.1080/22221751.2025.2490531 Jiang, Yawen Asia Observational Epidemiology Study Students Elementary (K-5) Middle/Jr High (6-8) High School (9-12) Viruses Respiratory symptoms Seasonal variation Vaccine effectiveness Primary and secondary school students Public health Test-negative case-control study This study found 57.1% influenza vaccine effectiveness among Shenzhen students in winter 2023/24. Protection was stronger for B/Victoria than A(H3N2), and effectiveness decreased with age.