38 / 2025-03-12 10:05:17

The Optimal Strategy for Seasonal Influenza Vaccination to Prevent High-Intensity Level of Influenza Epidemics in Zhejiang, China: An Integrated Transmission-Dynamic and Health-Economic Modeling Analysis

Seasonal influenza vaccination,Susceptible-vaccinated-infectious-recovered-susceptible model,Decision tree,Optimal vaccination strategy

Background: Although Seasonal Influenza Vaccination (SIV) is a crucial preventive measure, achieving sufficient coverage to completely control influenza epidemics poses a significant challenge. This study aims to evaluate optimal strategies for SIV to prevent high-intensity level of influenza epidemics in Zhejiang Province, China.

Methods: This study estimated the incidence of influenza from 2018 to 2023 in Zhejiang Province, China, using influenza weekly surveillance data. We developed a Susceptible-Vaccinated-Infectious-Recovered-Susceptible (SVIRS) model to simulate influenza transmission and used a decision tree to assess eight vaccination strategies aimed at preventing high-intensity influenza outbreaks. These strategies varied in vaccine allocation across three age groups: children (0-14 years), adults (15-59 years), and the elderly (60+ years). High-intensity outbreaks were defined as weekly incidence rates above 72.2 per 100,000.

Results: The SVIRS model indicated that achieving a 36.17% vaccination coverage among the total population could prevent influenza epidemics from reaching high-intensity levels. Prioritizing children or the elderly for vaccination was most effective, reducing the weekly incidence rate to 10.12/100,000 and offering the best cost-effectiveness, saving 23.45 yuan per capita and gaining 0.0102 Quality-adjusted life Days (QALDs). When significantly increasing pediatric vaccination is challenging, reallocating focus to adults is the second-best option, saving 14.46 yuan per capita and gaining 0.00092 QALDs annually.

Conclusion: Achieving a vaccination coverage beyond 36.17% is projected to prevent high-intensity level of influenza epidemics. Targeting children or the elderly is most cost-effective; in pediatric challenges, reallocating some focus to the 15-59-year-olds is a highly cost-effective second strategy with higher feasibility.