Measuring the Social and Externality Benefits of Influenza Vaccination

Vaccination represents a canonical example of externalities in economics, yet there are few estimates of their magnitudes. I provide evidence on the social and externality benefits of influenza vaccination in two settings. First, using pre-existing differences in state-level vaccination rates interacted with exogenous variation in vaccine quality, I provide causal estimates of the impacts of aggregate vaccination rates on mortality and work absences in the United States. Scaled nationally, I find that a one percentage point increase in the vaccination rate results in 985 fewer deaths and 7.5 million fewer work hours lost due to illness each year. The mortality effects are concentrated among individuals 75 and older, but 35-85% of the benefits are driven by the vaccination of people under 75, suggesting a considerable externality effect. Second, I examine a setting in which vaccination is targeted at a group with high externality benefits: influenza vaccination mandates for health care workers. I estimate that these mandates lead to a 17% decrease in hospital admissions with an influenza diagnosis. For both the general population and the population of health care workers, I calculate the monetary benefit per vaccination and find that these benefits are large in comparison to the costs of vaccine administration.