Another state appears poised to tighten its vaccination “opt-out” law.

In Maine, the state Senate passed a bill to eliminate non-medical vaccination exemptions. The bill now goes to Gov. Janet Mills, who has voiced her support, the Associated Press reported.

Like Idaho and most other states, Maine now allows parents to opt-out of vaccinations on religious or philosophical grounds.

Maine would join three other states that already ban non-medical opt-outs: California, Mississippi and West Virginia. Other states are also looking at tightening their vaccination laws. Oregon, for example, is considering its own bill to ban non-medical exemptions.

Idaho’s vaccination opt-out rates are among the highest in the nation — driven largely by non-medical exemptions. In 2018-19, more than 7 percent of the state’s kindergartners, first-graders and seventh-graders attended school with at least one religious or personal exemption.