Factors associated with willingness to receive influenza vaccination among adults in Shanghai, China: a study based on the health belief model

Seasonal influenza imposes a substantial disease burden, yet the vaccination rate in China remains relatively low. So far, research on vaccination willingness has mainly focused on particular groups, such as children, the elderly, and pregnant women. Limited studies have been carried out on the general adult population, which is vital in disease spread. This study aimed to explore the willingness of adults in Shanghai to be vaccinated against influenza and to identify the factors that effectively drive the willingness among the general adult population. A cross-sectional survey was conducted from July to December 2024 among adults aged 18 years and older in Shanghai, China. Data were collected regarding demographic information, constructs of the Health Belief Model (HBM), knowledge of influenza vaccine, and willingness to receive influenza vaccination. Multivariable logistic regression analyses were performed to examine associations between these variables and willingness to be vaccinated. Structural Equation Modeling (SEM) was employed to quantify direct and indirect pathways linking HBM constructs to vaccination willingness. A total of 1786 participants were enrolled in the study. Of these, 9.6% were unwilling to receive influenza vaccination, 32.8% were uncertain, and 57.6% were willing to be vaccinated. Females (AOR = 1.31, 95%CI: 1.03–1.68) and participants self-reported as being in poor health (General: AOR = 2.01, 95%CI: 1.23–3.30; Unhealthy: AOR = 2.35, 95%CI: 1.42–3.92) were more likely to get vaccinated. In terms of HBM constructs, perceived barriers (direct effects: standardized β = -0.27, p < 0.01) exhibited a significant negative correlation with adults’ willingness to receive influenza vaccination. Conversely, cues to action were positively associated with vaccination willingness (total effects: standardized β = 0.70, p < 0.01), with perceived barriers significantly mediating this relationship (standardized indirect effect β = 0.18, p < 0.01). This study revealed that cues to action were significant predictors of adults’ willingness to receive influenza vaccination, which not only had direct impacts on the willingness but also exerted indirect effects through the reduction of perceived barriers.