Demonstrators in Olympia, Wash., rally against a plan for stricter vaccination requirements in February. (Ted S. Warren/AP)

The Washington state Senate narrowly passed a measure late Wednesday that would make it harder for parents to opt out of vaccinating their children against measles in response to the state’s worst outbreak in more than two decades.

The bill, which would eliminate personal or philosophical exemptions from the measles, mumps and rubella (MMR) vaccine, is a victory for public health advocates who had not expected it to make it to the floor.

The measure passed 25 to 22 in the Democratic-controlled chamber, after being brought to the floor just minutes before the legislative deadline. No Republicans voted in favor, and two Democrats voted against.

The bill is expected to pass the House, where a nearly identical measure was approved last month, and be signed into law by Gov. Jay Inslee (D). It would be the first time in four years a state has removed personal exemptions in the face of growing anti-vaccine sentiment. California and Vermont removed personal exemptions in 2015. Other states have tightened vaccination requirements but have not removed exemptions.

The bill’s 11th-hour passage in the Senate comes as the resurgent disease approaches record numbers and other states weigh similar legislation to close loopholes or eliminate personal or religious exemptions from vaccination requirements.

Inslee, who pushed lawmakers to support the measure, is running for president on a platform centered on evidence-based science and climate change. The vaccine debate has pitted advocates of science and public health, who reflect the majority of Americans who support vaccinations, against a minority of anti-vaccine activists, who raise issues of personal choice and false claims about vaccines.

The stricter rule would apply only to immunizations for measles, mumps and rubella. Parents would still be able to cite personal or philosophical exemptions to avoid other required school vaccinations for their children. Religious and medical exemptions will still be allowed for all vaccinations, including MMR.

Advocates and lawmakers were able to overcome strong lobbying by anti-vaccine groups, which are among the most vocal and organized in the country. Those groups mobilized hundreds of supporters, who telephoned and sent emails to lawmakers, turned out for public hearings and proposed poison-pill amendments, intended to weaken a bill or ruin its chances of passing.

Republicans appeared to be close to killing the bill before a last-minute flurry of action.

Sen. Annette Cleveland, the Democrat who sponsored the bill, spent more than two hours during the floor debate Wednesday refuting misinformation about the safety of the MMR vaccine and measles risk for children. She told colleagues that a vote against the bill would be “a vote against public health, a vote against the safety of our public spaces.”

After the measure passed, she referred to the “unfortunate reality today that many people embrace conspiracy theories and alternative facts more readily than proven science.”

“It’s even more disappointing,” she said in a statement to The Washington Post, “when you hear colleagues across the aisle share their constituents’ unsubstantiated Internet theories over the expert knowledge of our country’s best medical minds at the Centers for Disease Control and Prevention.”

Republican senators opposed to the measure spoke repeatedly about government overreach. “I really believe parents should have the right to decide what type of medical procedures to use on their children, and that’s especially true of little ones,” said Sen. Mike Padden (R).

The bill’s House sponsor, Rep. Paul Harris, a moderate Republican whose Clark County district is at the center of the outbreak, stood firm, saying his constituents overwhelmingly supported the measure.

“People are forgetting what some of these diseases are like,” he said Thursday. “I hope this will get more kids vaccinated, which is the ultimate goal of all this. . . . We forget that science is what has made a huge difference in our society. Community immunity trumps personal freedom at times, especially what’s going on now with all the measles outbreaks.”

Immunization advocates were overjoyed by the bill’s passage.

“We are elated!” said Sarah Rafton, executive director of the Washington Chapter of the American Academy of Pediatrics.

WCAAP President Rupin Thakkar blamed dangerous measles outbreaks on the rise of vaccine exemptions for personal beliefs and applauded the legislature for eliminating them. “The recent measles outbreak served as an alarm, and today our legislators bravely stood with facts over fiction,” he said.

Other state and local efforts to control outbreaks are pushing back against those opposed to mandatory vaccinations: On Wednesday, New York City’s Board of Health extended its order to vaccinate everyone in four hard-hit Zip codes in Brooklyn that are home to tens of thousands of ultra-Orthodox Jews after a group of parents brought a lawsuit.

On Thursday, New York City health officials said they issued summonses to three parents who face $1,000 fines for not getting their exposed children vaccinated. Officials also ordered four schools to be closed for failing to comply with emergency orders. One school that had been closed was reopened.

Earlier in the week, officials in Rockland County, N.Y., barred all unvaccinated people who have been exposed to the disease from public gathering places, including houses of worship, for up to three weeks. “Need we wait for someone to die?” Rockland County Executive Ed Day said in announcing the measure.

Campaigns to toughen state requirements in Iowa, Colorado, Maine and Oregon also face strong opposition. Washington is one of 17 states that allow exemptions from required immunizations for personal or philosophical beliefs.

The outbreak there prompted Inslee to declare a state of emergency Jan. 25, after officials reported 25 measles cases. As the numbers shot up — 78 measles cases in Washington and neighboring Oregon have been confirmed, among 555 cases nationwide across 20 states — lawmakers in Olympia, Wash., began weighing legislation to eliminate personal or philosophical exemptions.

If the outbreaks are not brought under control, health officials worry measles cases in 2019 will set an all-time high nearly two decades after the vaccine-preventable respiratory disease was “eliminated” in the United States. Before vaccines were introduced, measles sent tens of thousands of Americans to hospitals each year and killed an estimated 400 to 500 people, many of them young children.

Public health officials had worried the bill was headed for defeat, which would have suggested “a very vocal minority has a disproportionate amount of influence on an issue that impacts everybody,” said Michael Fraser, chief executive for the Association of State and Territorial Health Officials.

“We need to look at the tactics used by opponents to better understand how these could play out in other states, and address those issues head on anticipating similar arguments,” he added after the vote.

Rafton said there is broad public support for the safety and efficacy of childhood vaccinations and noted that 98 percent of children in the United States are immunized. But in Washington, the state’s vaccination rate for kindergarten-age children for the 2017-2018 school year was 86 percent — well below the 95 percent state target to effectively prevent the spread of most diseases.

About 4.7 percent of the parents or guardians of Washington kindergartners claimed an exemption to at least one vaccine — over twice the national rate, according to state Health Department data for 2017-2018.

Nearly 9 of 10 children with nonmedical exemptions had parents or guardians who claimed personal or philosophical reasons.

Until Wednesday, the bill’s supporters were not optimistic about its chances. A handful of Democratic senators had been uncomfortable with the measure, Rafton said. “One senator has been hesitant because a family member had a reaction to a vaccine,” she said.

Last-minute maneuvering allowed the bill to be called for a vote. A procedural squabble nearly derailed the debate, which was further delayed by a fire alarm that forced the evacuation of the building where Senate staff and many members have their offices. Republican senators proposed 18 amendments to delay, weaken or alter the bill, all of which were either withdrawn or defeated. One amendment would have lessened protection for the youngest children, who are most at risk for serious measles complications.

Heading into the vote, medical groups were at a disadvantage because they were not able to mobilize supporters in the same way as anti-vaccine activists.

Medical groups didn’t want to have “doctors and parents facing off in the hallways,” Rafton said. As a result, “we haven’t been able to represent our members with that same sort of palpable presence, despite pediatricians’ clear opinions that the law should change.”

Doctors also want to keep a dialogue going with “the parents who worry and wonder about getting shots,” she said. “So we want to take the high road in advocacy. We find when doctors are thoughtful and truly listening to parents, over time, they’re able to get the right information.”

Read more:

The unique dangers of the Washington state measles outbreak

Unaware he had measles, a man traveled from New York to Michigan, infecting 39 people

Do I need another MMR vaccine shot and other questions about measles