unvaccinated children

Khadra Abdulle, a resident of St. Paul, stops to shop at the Riverside Market in the Cedar-Riverside neighborhood of Minneapolis. It's the inaccurate information about a link between vaccines and autism, she says, that's keeping some well-meaning parents from getting their kids vaccinated against measles. Mark Zdechlik/MPR hide caption

Sara Martín reads bedtime stories with her children. When the kids were younger, she says, staying up to date on their frequent immunizations was tough, because of cost and transportation issues. Lauren M. Whaley/CHCF Center for Health Reporting hide caption

California is one of 20 states that allow parents to opt out of vaccination requirements for reasons of "personal belief." About 10 percent of students in the Santa Monica-Malibu school district are not immunized. Justin Sullivan/Getty Images hide caption