The fight over measles is moving from the streets of Williamsburg to the gilded halls of the State Capitol in Albany.

There, lawmakers, local politicians and anti-vaccination activists are girding for a fight over the state’s rules that allow parents to keep their children unvaccinated for religious reasons. State senators are proposing to eliminate the religious exemption, citing it as a key reason for the spread of measles.

“You have a First Amendment right to practice your own religion, but you do not have the right to endanger your children or worse other people’s children,” state Sen. Brad Hoylman, a Democrat from Manhattan, said at a press conference in Albany Monday.

Hoylman, the sponsor of S2994, and fellow supporters argue that the sizable number of unvaccinated children in Rockland County and Brooklyn—many of whom have religious exemptions—has made fighting the current measles outbreak more difficult.

An estimated 28 percent in kids in Rockland County weren’t vaccinated for measles, while an estimated 14 percent of pre-school aged children in Williamsburg weren’t, according to recent estimates from local health departments.

Listen to Gwynne Hogan’s report on WNYC:

Joining the press conference was county executive for Rockland, Ed Day, who has been engaged in legal and logistical challenges to slow the spread of measles in his jurisdiction.

“This needs to be done, not tomorrow, not in a week, not in a month, and not in a year. It must be done immediately, the numbers are gaining strength,” Day said.

Also Monday, the Centers for Disease Control and Prevention announced that there have been 704 measles cases across 22 states so far this year.

The religious exemption law has been on the books in New York since 1968, according to the State Health Department. Hoylman’s bill was introduced in January and is in the Health Committee; it’s unclear if they have enough votes to pass the bill.

Meanwhile anti-vaccination activists are lining up to oppose the bill under the umbrella group New York Alliance for Vaccine Rights. They have planned a rally in Albany on May 14th, where anti-vaccination activists from the national circuit are expected to speak. The group is aiming to raise $20,000 and has received more than $14,000 from 211 people as of Monday. Organizers didn’t return a request for comment right away.

These opponents of mandatory vaccination have been galvanized in recent months by the measures taken by local governments intended to slow the spread of measles, including Rockland County’s ban on unvaccinated children in public places (temporarily struck down in court) and New York City’s vaccination rule in certain Brooklyn zip codes (which a court upheld).

Activist Stephanie Mahairas, who said her son was injured by a vaccine, has been to rallies in both locations. At a recent court hearing in Brooklyn, she told reporters she would fight the removal of the state’s religious exemption.

“It goes against the constitutional rights; the Civil Rights Act of United States of America, gave children the right to go to school based on their religion, race, sex and nation of origin,” she said “So this is against the Civil Rights Act.”

After New York City Mayor Bill de Blasio announced the emergency order in Brooklyn, Governor Andrew Cuomo appeared sympathetic to opponents of mandatory vaccination.

“It's a serious public health concern; but it's also a serious First Amendment issue and it is going to be a constitutional legal question,” Cuomo said on WAMC radio. “Do we have the right to society, government have the right to say; you must vaccinate your child because I'm afraid your child can affect my child?”

But on Monday, Cuomo clarified his opinion and said he supported mandatory vaccination under the current circumstances.

“We’re in a world now, where if I sneeze, you catch a cold. Your health is not just your health. Your health is my health,” Cuomo said at a press gaggle. “I don’t think, in this case, the religious exemption is appropriate.”

Most states allow religious exemptions. Only three don't: Mississippi, West Virginia and California. California eliminated its religious exemption in 2015 in response to a measles outbreak that was tracked back to Disneyland. That law did raise the state's vaccination rates, but the number of medical exemptions has more than tripled in the subsequent years, suggesting some parents were trading religious exemptions for medical ones. Now lawmakers are are trying to craft new legislation, giving the state more oversight to vet medical exemptions, but it's facing pushback from parents there who oppose mandatory vaccination.

As of Monday, New York City has seen 423 measles cases since the outbreak began in October. Under the emergency vaccination rule, the city has now fined 57 people for failing to get vaccinated; they each face $1,000 fines if a judge upholds the charges. Twenty-nine people have been hospitalized, including six in the intensive care unit. Seventeen people caught pneumonia as a complication.

Children account for 85 percent of those sickened, and 92 percent of those kids were completely unvaccinated, according to the city’s health department. A total of 60 cases have occurred among adults, of whom 72 percent were either unvaccinated or had an unknown vaccination status. There are no deaths associated with the outbreak.

Another 236 measles cases have been reported in other parts of New York, mostly in Rockland County. Mayor Bill de Blasio and New York State Governor Andrew Cuomo didn’t return request for comment on the bill.

Gwynne Hogan is an associate producer at WNYC. You can follow her on Twitter at @GwynneFitz.