Influenza vaccine hesitancy versus uptake in seven Chinese megacities: a cross-sectional survey

BACKGROUND: Influenza vaccine hesitancy remains a major barrier to achieving adequate vaccination coverage, particularly in densely populated urban areas with aging populations. Seven Chinese megacities are especially vulnerable to influenza transmission, yet evidence on drivers of vaccine hesitancy in these contexts remains limited. This study aimed to assess the prevalence and determinants of influenza vaccine hesitancy (IVH) among urban populations to inform strategies for improving vaccine uptake in China. METHODS: We conducted a multi-city cross-sectional survey from March to June 2025 across seven Chinese megacities (Beijing, Shanghai, Guangzhou, Shenzhen, Tianjin, Chongqing, and Chengdu). Participants were selected using a stratified sampling strategy within communities; eligible participants were residents (aged ≥ 18 years) who had lived in the selected communities for at least six months. Data on demographic, socioeconomic, attitudinal factors, and behavioural factors were collected. Multivariable logistic regression was used to identify factors associated with IVH and pre-season influenza vaccine uptake. RESULTS: A total of 8689 participants were included. Overall, 45% of participants were classified as vaccine hesitant, while the self-reported influenza vaccination coverage for the 2024 season was 30%. Substantial variation in hesitancy was observed across megacities. Older adults (≥ 65 years) were less likely to report IVH than younger adults (18-44 years) [adjusted odds ratio (aOR) = 0.72, 95% confidence interval (CI): 0.55-0.93] and more likely to be vaccinated (aOR = 1.63, 95% CI: 1.35-1.96). Psychosocial factors were the strongest predictors of hesitancy, particularly low perceived vaccine benefit (aOR = 11.18, 95% CI: 8.45-14.64) and low trust in health authorities (aOR = 17.13, 95% CI: 13.51-21.71). Vaccination uptake was primarily associated with behavioural factors, especially prior COVID-19 vaccination (aOR = 0.32, 95% CI: 0.25-0.39). CONCLUSIONS: Influenza vaccination in Chinese megacities is driven by a mix of demographic, psychosocial, and behavioural factors. Targeted strategies addressing both hesitancy and uptake are needed to improve coverage and reduce influenza transmission.