Rates of Unvaccinated Children Tripled in the United States, with Vaccine Refusal Highest for MMR and Polio: An Analysis of the National Immunization Survey (NIS), 2002-2010

Laura Blakeslee, University of Wisconsin-Madison

Using data from the National Immunization Survey, a nationally-representative annual sample of 20,000 children in the United States, this analysis finds rates of un-vaccinated children nearly tripled between 2002 and 2007 (from 0.27% to 0.80%) and remained consistently high through 2010. This trend supports epidemiological evidence that recent outbreaks of vaccine-preventable disease have occurred in communities with high rates of un-vaccinated children. However, while vaccine refusal is highest among White children, larger households, households in the western U.S. and in states that allow philosophical exemptions from immunization, this analysis concludes larger (and increasing) proportions of children are un-vaccinated against specific diseases: Measles, Mumps & Rubella (MMR)=7.8%; Polio=2.7%; Haemophilus influenzae type b (Hib)=2.5%; Hepatitis B=2.2%; and Diphtheria, Tetanus & acellular Pertussis (DTaP)=2.2% (representing 132,000-482,000 un-vaccinated children across the country). These findings suggest new interventions are needed to reduce future outbreaks by focusing efforts on an increasingly diverse population of un-vaccinated children.