The state Senate moved Thursday to end philosophical but not religious exemptions to vaccines, amid rising concerns about disease outbreaks.

In an initial round of voting, the Senate voted 20-15 to pass a bill that would end both kinds of opt-outs by 2021 for schoolchildren, as well as employees at nursery schools and health care facilities. But the chamber then tacked on an amendment to keep the religious exemption in place.

A number of states and municipalities are considering similar bills in an attempt to reduce the number of people opting out of routine childhood vaccinations and increase immunization rates. Federal data shows Maine has among the highest rates of non-medical vaccine exemptions.

Supporters of the bill point to the rising number of cases nationwide of measles — including outbreaks this year in the Pacific Northwest and New York — and argue that some people who choose not to vaccinate their children are relying on a long-debunked claim that the measles, mumps and rubella vaccination increases the risk of autism. They also say the bill will help protect children who can’t be vaccinated for medical reasons.

Opponents of the bill have expressed concern that it could stigmatize unvaccinated children and would infringe on parental rights.

The original bill has already passed the state’s House, but now lawmakers there must consider the amendment. The bill also still faces further action in the Senate. Democratic Gov. Janet Mills’ administration has said it supports the measure.

Schools and many health care facilities typically require vaccinations, but Maine is among 17 states that allows some non-medical exemptions for “personal, moral or other beliefs,” according to the National Conference of State Legislatures.

Maine’s bill has drawn passionate arguments on both sides.

Kate Herrold said Thursday that vaccines are safe and that she wants to protect those who cannot receive vaccines, including children with cancer and others with compromised immune systems.

“I understand their opposition and their belief that it’s a choice and I respect that,” Herrold, of Falmouth, said, as she held her 1-year-old daughter in the Statehouse hallways. “At the end of the day, It’s a choice that doesn’t just affect them.”

Bethany Allgrove, of Lincolnville, who opposes the bill, said she didn’t think it would have its intended effect.

“I think that they’re not going to move the needle on increasing vaccination rates,” said Allgrove while holding her infant son.

Instead, she said, families might simply leave Maine.

The state doesn’t know exactly how many students are not vaccinated for religious or philosophical reasons, but the Department of Education has estimated that as many as 5% — or 9,032 students — may have non-medical exemptions.

Survey data from the Maine Center for Disease Control and Prevention shows that nearly 2,000 Maine kindergarteners, seventh-graders and high school seniors currently have such exemptions. Nearly all such students were exempted on philosophical grounds.