ST. PAUL (AP) - Some smaller Minnesota schools and districts are seeing higher rates of parents opting out of vaccinating their children than their larger counterparts.

State data show 16 districts had at least 10 percent of kindergartners opt out of vaccines last year, with 32 more schools between 5 percent and 10 percent. The districts tended to have kindergarten classes of fewer than 100 students.

Statewide, less than 3 percent of kindergartners went without vaccination. Schools in the Twin Cities saw opt-out rates of roughly 1 percent.

Ben Christianson, an epidemiologist with the Minnesota Department of Health, says it's not clear why some schools have higher opt-out rates for vaccines. Parents can opt of a state requirement for vaccination for medical or philosophical reasons.