A Human Mobility-Based Modeling Study of Influenza Vaccination Strategies Across Socioeconomically Disparate Regions in China

Background: China‘s influenza vaccination coverage remains at a low rate, with significant regional socioeconomic disparities, lacking targeted distribution strategies and achievable coverage targets. This study aims to provide scientific evidence for formulating differentiated and feasible vaccination strategies across Chinese provinces based on regional economic gradients. Methods: We employed the Susceptible-Vaccinated-Exposed-Asymptomatic-Infectious-Critical-Fatal-Recovered/Removed (SVEAICFR) model to simulate various vaccination strategies, analyzing the reduction in disease burden and vaccine dose requirements across underdeveloped, developing, and developed regions. The optimal strategy and achievable coverage targets were subsequently determined. Results: The 31 provinces were clustered into three categories based on economic levels, showing significant spatiotemporal differences in epidemics (Kruskal–Wallis test, all p < 0.001). Developed regions showed the earliest onset and highest peaks (influenza-like illness positive (ILI+) index ≈ 12–13, Baidu Influenza Search Index (BISI) ≈ 310,000). Developing regions exhibited moderate lagging by 1–2 weeks, while underdeveloped regions had the lowest peaks (ILI+ 3–4) and longer epidemic cycles. During the 2023–2024 influenza season, the national predicted vaccination rate was only 2.89% with marked regional disparities. Baseline incidence, severity, and mortality rates were 13,374.93, 49.52, and 8.37 cases per 100,000 population, respectively. Modeling indicates that increasing influenza vaccination coverage rates for populations aged <18 and ≥65 to a theoretical threshold (39.73% of the total population) before the season could reduce incidence, severity, and mortality rate by 99.26%,99.42%, and 99.46%, respectively. Conclusions: Influenza prevalence in China exhibits significant regional heterogeneity, necessitating differentiated measures based on regional economic gradients. Regional support mechanisms should be implemented to promote equitable vaccine distribution. Priority vaccination for high-risk populations (aged <18 and ≥65), to reach a 40% theoretical national coverage target, is recommended via realistic implementation pathways to minimize the disease burden of influenza.