AUGUSTA, Maine (AP)   Maine health officials say vaccination opt-out rates for the state’s kindergarteners increased during the 2017-2018 school year.

According to a report released this week by the Maine Center for Disease Control & Prevention, 5 percent of kindergarteners were opted out by their parents this year for philosophic of religious reasons. The Portland Herald Press reports Maine’s rate last school year was more than twice the national average of 1.8 percent.

Health officials say low vaccination rates are responsible for outbreaks of preventable diseases. Maine has one of the highest rates of pertussis–a contagious respiratory disease–in the country.

Health officials say stricter vaccination standards will prevent future outbreaks. They point to states like California which eliminated non-medical exemptions in 2015 following a measles outbreak.