Influenza vaccine uptake among children and older adults in China: A secondary analysis of a quasi-experimental study

Abstract Background: Influenza vaccination is the key to reducing the influenza-related disease burden, especially among high-risk populations. However, influenza vaccine uptake is low in China. This secondary analysis of a quasi-experimental trial in Guangdong Province aimed to understand factors associated with influenza vaccine uptake among children and older people stratified by funding context. Methods: A total of 225 children (aged 0.5-8 years) and 225 older people (aged 60 years or above) were recruited from three clinics (rural, suburban, urban). Participants were allocated into two groups based on different funding contexts: self-paid group (N=150, including 75 children and 75 older adults) in which participants paid full market price for their vaccination; and subsidized group (N=300, including 150 children and 150 older adults) in which varying levels of financial support was provided. Univariable and multivariable logistic regressions were conducted stratified by funding contexts. Results: Overall, 75.0% (225/300) of participants in the subsidized group and 36.7% (55/150) in the self-paid group got vaccinated. Older adults had lower vaccination rates than children in both funding groups, while both age groups showed much higher uptake in the subsidized group than in the self-paid group (86.7% vs 53.3% among children; 63.3% vs 20.0% among older people). In the self-paid group, participants living with children (aOR:2.61, 95%CI: 1.06-6.42) or older people (aOR:4.76, 95%CI: 1.08-20.90) having prior influenza vaccination in the same household were more likely to be vaccinated; trust in providers’ advice (aOR=4.95, 95%CI:1.99, 12.43) or effectiveness of the vaccine (aOR: 12.18, 95%CI: 5.21-28.50), and experienced influenza-like illnesses in the family (aOR=46.52, 4.10, 533.78) were associated with higher vaccine uptake in the subsidized group. Conclusions: Older people had suboptimal vaccine uptake compared to children in both contexts and need more attention in future efforts to enhance influenza vaccination. Tailoring interventions to different vaccine funding contexts may help improve influenza vaccine uptake: In self-paid context, measures to motivate people to accept their first ever influenza vaccination may be a promising strategy. In subsidized context, strategies to improve public confidence in vaccine effectiveness and providers’ advice would be useful. Trial registration: ChiCTR2000040048. Registered on November 19, 2020.