Association for Public Policy Analysis & Management

Each year 2.1 million children in the United States 19 to 35 months of age have not received the fully recommended schedule of vaccinations. Most undervaccinated children -- those who have received some, but not all, of their recommended vaccinations -- come from poor, minority, single-mother households; however, a growing number of children from affluent families are not being vaccinated due to parental choice. This drop in immunization rates in the United States has contributed to the widespread reemergence of a number of vaccine-preventable diseases and has left the country vulnerable to outbreaks of other serious diseases. While the correlates of immunizations have been well-studied in the public health literature, few of these studies have attempted to establish causal links. We look at the role information plays in parents’ decisions about immunizing their children. In particular, we examine whether a local outbreak of a vaccine preventable disease changes parents’ perceptions of the risks of leaving their children unprotected and increases the chance that children are vaccinated on time. We find that outbreaks within a state do increase the rate of on-time immunizations and that these responses are largest for the children most likely to be under vaccinated.