Mayor Bill de Blasio announced on Wednesday that New York City will require all municipal workers—including first responders such as firefighters and police officers—to get at least one vaccine dose by October 29th. After that date, they will no longer be able to opt-out through weekly coronavirus testing.

As an incentive, city employees will have $500 added to their paychecks for receiving their first shot at a city-run vaccination site. Those who remain unvaccinated will be placed on unpaid leave until they show proof of inoculation to their supervisor.

“There is no greater privilege than serving the people of New York City, and that privilege comes with a responsibility to keep yourself and your community safe,” de Blasio said in a statement. “As we continue our recovery for all of us, city workers have been a daily inspiration. Now is the time for them to show their city the path out of this pandemic once and for all.”

The mayor said the order, which would be signed Wednesday by New York City Health Commissioner Dr. Dave Chokshi, would apply to approximately 160,500 city workers. That number does not include teachers and city healthcare employees, who are already required to get the vaccine. Of the remaining employees, about 71% have received at least one dose of COVID-19 vaccine.

The overall share of vaccinated employees has steadily climbed since the mayor first announced his "vax-or-test" rule in late July. The mayor's office said 83% of all municipal workers—roughly 305,000 people—had received at least one dose as of October 15th -- an increase of 18 percentage points. The size of the city's workforce fluctuates. When the mandates began to take hold in mid-August, there were around 367,000 city employees, but a spokesperson updated the figure Wednesday afternoon to 378,000.

But the city has struggled to convince certain groups, notably first responders, to get the shot. Only 69% of police officers have been vaccinated to date. The rate for city firefighters is even worse, that of 59%.

And amid surging coronavirus cases within the city's main jail complex on Rikers Island, only half of those working in the city's Department of Correction (DOC) have been immunized—the poorest vaccination rate of any city agency. Civilian DOC employees and its uniformed members working in healthcare settings must also immediately comply with the mandate. But to avoid adding to the DOC's staffing crisis, other uniformed members have more leeway, and their mandate doesn't take full effect until December 1st.

De Blasio's decision will likely draw protests from some municipal unions, which have sued over full vaccine mandates for teachers and health care workers. But those efforts have failed to overturn the policy. Early this month, Supreme Court Justice Sonia Sotomayor denied a request from a group of New York City teachers to prevent the mayor from implementing the mandate.

Nevertheless, Patrick Lynch, the president of the Police Benevolent Association, said a lawsuit was forthcoming from his police union. “Now that the city has moved to unilaterally impose a mandate, we will proceed with legal action to protect our members’ rights," he said.

At a news conference in Manhattan hours after the mayor's announcement, United Firefighters Association President Andrew Ansbro said the order immediately impacts more than 3,500 active duty first responders who are unvaccinated -- or 45% of FDNY’s total workforce. Ansbro warned that if these firefighters are sent home, it could lead to severe staff shortages at firehouses, which would then need to be temporarily closed.

“It's very hard to staff a firehouse as it is,” said Ansbro, who is vaccinated. “We'll definitely be closing firehouses if the amount of people that have told me they're not going to get vaccinated...if they get sent home, there's going to be a serious operational problem.”

Ansbro claimed that FDNY had reached herd immunity, given 55% of active duty firefighters have taken at least one dose of COVID-19 vaccine while over 70% of this workforce has recovered from the virus itself. He added those who’ve previously contracted COVID but have not been vaccinated should be exempt from receiving the vaccine. Public health experts disagree with this claim given immunity after a natural infection can be potent but on a much less consistent basis relative to vaccination.

Ansbro said the union will be exploring “all avenues” with other municipal unions to fight the mandate, keep the testing alternative and ensure that vaccination is "a personal choice."

But Henry Garrido, the head of District 37, the city's biggest municipal union, signaled their leadership was willing to negotiate with the city.

“We encourage all our members to get vaccinated to protect themselves and their families. The proposed mandate must be collectively bargained and we expect City Hall to slow down and sit down with us," Garrido said.

The city will begin bargaining immediately with unions over the mandate. Religious and medical exemptions will be permitted. But the mayor made it clear that those who fail to comply would face strong consequences.

"The bottom line is we're not going to pay people unless they're vaccinated. They'll lose their jobs," de Blasio said during a Wednesday interview on MSNBC.

New York City now joins a host of other cities, including Los Angeles and Seattle, that have issued strict vaccine mandates. Similarly, President Joe Biden has also required vaccinations for a majority of federal workers and contractors.

De Blasio, who is said to be mulling a run for New York governor next year, has tried to position the city as a national leader in the vaccination effort. His initial vax-or-test policy was held up as an example by President Biden. The move to impose a stricter mandate, which de Blasio had been hinting at for more than a month, comes with nine weeks to go in his mayoral term.

"We've got to end the COVID era," he told MSNBC. "Our police officers, our EMTs, our firefighters, all our public employees, a lot of them come in very close contact with their fellow New Yorkers. They need to be safe, their families need to be safe, but we also need to reassure all New Yorkers, that if you're working with a public employee, they're vaccinated."

During his morning press conference at City Hall, the mayor faced several questions about whether it was fair to give $500 to city employees who had held out on getting vaccinated when others went without such a benefit. All told, the payouts from the incentive program could cost the city as much as $23 million.

De Blasio argued that the city had taken incremental steps to convince more people to get vaccinated. He also noted the ongoing backdrop of "massive misinformation" around the vaccine.

"I'm coming from a very practical place to get us to a goal. And I think this is a smart incentive to help get us there," de Blasio said.

This story was updated with the latest size of the city's workforce and quotes from Mayor Bill de Blasio and union leaders.