It runs in the family – influenza vaccination and spillover effects

We study a population-based influenza vaccination program in the Netherlands, and the spillovers it has within families. Individuals aged 65 years and over qualify for the program and receive a personal invitation for a free flu shot, while ineligible individuals have to pay out-of-pocket and face additional barriers to getting vaccinated. The quasi-random variation at age 65 is exploited to analyse program impact on vaccination behavior of cohabiting partners and adult children. We find that the program induced a 10 percentage points increase in vaccination coverage among individuals at age 65. The program further led to a similar effect on vaccination take-up by cohabiting younger partners, but spillovers on children were negative. These asymmetric patterns of vaccination uptake are consistent with partners and children learning about influenza mortality risk, target group membership, and cost and benefits of vaccination, as well as salience. We conclude that public health campaigns should pay attention to the effects on voluntary preventive care participation as within-family spillovers impact the program’s overall public health impact.