Real-World Effectiveness of the Influenza Vaccine in Young Children

Influenza causes substantial illness among children. RCTs demonstrate that the influenza vaccine reduces active-surveillance-detected influenza but have insufficient samples to examine outcomes such as health care provider visits. This study documents that children whose well-child visits occur when the seasonal influenza vaccine is broadly available are 23.4 pp more likely to be vaccinated than children whose visits do not. Using large administrative health care datasets, we leverage this vaccination-rate variation to show that the vaccine reduces outpatient and ED visits significantly. The results imply that making pediatric influenza vaccinations more convenient could substantially increase vaccination rates and reduce health care expenditures.