Out-of-pocket payments and community-wide health outcomes: an examination of influenza vaccination subsidies in Japan.

While studies have shown that reductions in out-of-pocket payments for vaccination generally encourages vaccination uptake, research on the impact on health outcomes has rarely been examined. Thus, the present study, using municipal-level survey data on a subsidy programme for influenza vaccination in Japan that covers the entire country, examines how reductions in out-of-pocket payments for vaccination among non-elderly individuals through a subsidy programme affected regional-level influenza activity. We find that payment reductions are negatively correlated with the number of weeks with a high influenza alert in that region, although the correlation varied across years. At the same time, we find no significant correlation between payment reductions and the total duration of influenza outbreaks (i.e. periods with a moderate or high alert). Given that a greater number of weeks with a high alert indicates a severer epidemic, our findings suggest that reductions in out-of-pocket payments for influenza vaccination among the non-elderly had a positive impact on community-wide health outcomes, indicating that reduced out-of-pocket payments contributes to the effective control of severe influenza epidemics. This suggests that payment reductions could benefit not only individuals by providing them with better access to preventive care, as has been shown previously, but also communities as a whole by shortening the duration of epidemics.