Nearly one in seven public and private schools have measles-vaccination rates below 90 percent, a rate considered inadequate to provide immunity, according to a USA Today analysis of data in 13 states.
Hundreds of thousands of students attend schools—ranging from small, private academies in New York City to large public elementary schools outside Boston to Native American reservation schools in Idaho—where vaccination rates have dropped precipitously low, sometimes under 50 percent.
The 13-state sample shows that people opposed to vaccinations tend to live near each other, leaving some schools dangerously vulnerable, while other schools are fully protected.