We Oregonians like to think of ourselves as an independent lot, but sometimes that independence threatens more harm than good. Knowing that, it’s time lawmakers addressed the state’s shrinking childhood immunization rate by tightening its exemption policy dramatically.

Efforts to persuade parents to do the right thing and have their children immunized have failed.

Oregon lawmakers should remove exemptions for personal beliefs, philosophical or religious reasons. The only exemptions allowed should be for medical necessity.

Oregon’s most recent attempt to boost vaccination rates came in 2013, when the law was changed to require parents seeking vaccination exemptions to talk with their physicians or take an online course. At the time, the statewide exemption rate was 7 percent.

The change worked as intended, but only for a time. By 2015, the statewide exemption rate was down to 5.8 percent, but then in began to rise. Today’s rate, 7.5 percent, is even higher than it was in 2013.

That was clear in Lane County earlier this year, when at least eight schools in the Eugene-Springfield area were hit by whooping cough outbreaks that forced unvaccinated students to stay home.

It may be only a matter of time before schools in Deschutes County face a similar problem. Here, at least six schools in the Bend area are what the state calls “most vulnerable,” with less than 80 percent of students current on vaccinations. Students at another eight schools are “more vulnerable,” with between 89.9 and 80 percent current on vaccinations.

So far, lawmakers have avoided putting real teeth into the state’s immunization requirements. Approval of the 2013 measure was by no means unanimous, and a bill that would have ended exemptions, introduced in 2015, went nowhere. That must change.