In Maine, current state law permits parents to skip vaccines for their children by signing a form opting out on philosophic and religious grounds. In the 2017-18 school year, 5 percent of Maine children entering kindergarten – about 600 children statewide – had non-medical exemptions for immunizations, state statistics show.Thirty-one public elementary schools were reporting 15 percent or higher rates of unvaccinated kindergarten students, putting those schools and the surrounding community at greater risk for the return of preventable diseases such as measles, chickenpox and pertussis.

Dr. Linda Sanborn, a family physician and a Democratic state senator from Gorham, said advocates are focused on protecting children from infectious diseases such as measles. New York City is now experiencing a measles outbreak that started among unvaccinated children, with more than 180 cases in an Orthodox Jewish community, according to news reports. In 2014-15, a measles outbreak in California that started at Disneyland sickened hundreds.

The World Health Organization issued a report Thursday that said “vaccine hesitancy” has become a global health threat.

“We should be doing all we can for these children. Their safety is so important,” said Sanborn, a co-sponsor of a bill with Tipping, who said the birth of his daughter a year ago spurred him to think about public policy in different ways.

“When you have a child, it opens your eyes to a lot of issues that should be changed in this world to make it a better place for your kid and all children,” Tipping said. “Schools and day cares should be a safe place for children to attend.”

A bill to make it more difficult to opt out of vaccines – by requiring a medical professional to consult with parents and sign off on the exemption – died in the Legislature in 2015 after lawmakers upheld a veto by then-Gov. Paul LePage.

Gov. Janet Mills has not stated a position on the bill, but pro-vaccine advocates are confident and made the measure more strict by eliminating all non-medical exemptions rather than requiring another step to opt out, as the 2015 bill would have done.

Mills spokesman Scott Ogden said the governor will examine the merits of the bill.

“Governor Mills will carefully review any legislation to modify current state vaccination policy, and she encourages all parents to have their children vaccinated,” Ogden said in a statement. “As a general matter, she believes that vaccinations are critical to protecting the health and welfare of Maine people.”

Medical opt-outs in Maine are extremely rare – only 0.3 percent of all vaccine opt-outs were for medical reasons, such as a child with leukemia, according to state statistics.

Maine experienced an increase in pertussis cases in 2018, from 410 in 2017 to 446, according to the Maine Center for Disease Control and Prevention. Several schools reported outbreaks this fall, including in Scarborough, Biddeford and Kennebunk, and the Middle School of the Kennebunks canceled its annual community Thanksgiving dinner in response to pertussis outbreaks.

Maine’s pertussis rate of 27.7 cases per 100,000 population was the worst in the nation in 2017 – the latest year for state-by-state comparisons – and more than five times the national average, according to the U.S. Centers for Disease Control and Prevention.

State Rep. Beth O’Connor, R-Berwick, is skeptical of vaccine safety. She believes parents should have a choice to opt out and that banning the exemptions would infringe on parent choice.

“I think this bill is a very, very bad idea,” O’Connor said. “I believe people should have all of these exemptions available to them. This is very important in a free society.”

Immunizations are overwhelmingly safe, decades of research has proven, and are not linked to autism. A 1998 study that claimed a link between vaccines and autism has been retracted and disproven.

After the Disneyland outbreak, California eliminated all non-medical exemptions and its school vaccination rates improved substantially, with 99.9 percent of all kindergartners vaccinated for the 2017-18 school year.

At 5 percent, Maine had the seventh-highest rate of non-medical opt-outs in the country in 2017-18, according to the federal CDC. Oregon had the worst vaccination coverage, with 7.5 percent of students entering kindergarten with non-medical exemptions.

Peter Michaud, a nurse and attorney for the Maine Medical Association, said children who for medical reasons can’t be vaccinated, such as those with leukemia, are especially vulnerable to hospitalization or dying if they catch a vaccine-preventable disease.

Michaud said people are opting out of vaccines not because they have a philosophic or religious exemption, but because they incorrectly fear that the vaccines are unsafe.

“People are not getting the vaccines because of a misunderstanding of the science,” he said. “Children keep getting sick, avoidably.”