NEW YORK — All city workers must have at least one dose of the COVID-19 vaccine by 5 p.m. on Oct. 29 in order to work, Mayor Bill de Blasio announced Wednesday, prompting backlash from several union leaders, who said their groups planned to challenge the new mandate in court.

"If you're a city worker, you need to be vaccinated," de Blasio said at his daily briefing Wednesday. "We are here to keep you safe so you can keep everyone else safe. We need you to keep everyone around you in the workplace safe. We need you to make sure the people who you encounter, the people of this city, the residents of this city are safe. Everyone needs to be vaccinated."

As of Tuesday, 84% of the city’s workforce had gotten at least one COVID-19 vaccine dose, data provided by the mayor’s office showed. The NYPD, the FDNY and the Department of Sanitation, however, lagged behind the overall rate, with first-dose vaccination rates of 70%, 60% and 62%, respectively. 

Asked how the city would respond if a significant number of employees were to refuse the vaccine, de Blasio said he was confident that scenario would not arise, citing the success of San Francisco’s mandate for city workers. 

“What I think is obvious, after a lot of conversation with the leadership of all of our uniformed agencies is, people are there to do a job and they believe in the work,” he said. “Also, they’re there for a paycheck, of course. It’s a noble profession, but people want to get paid, and they want to accrue time towards that very, very important pension that they get later on, and folks are not going to give that up, by and large.”

“We obviously have contingencies in place for any gaps that we experience, but our uniformed agency leadership feel very strongly that they will be able to handle any scenario,” he added.

In a statement released shortly after the announcement of the mandate, which was intially revealed in a press release early Wednesday morning, Police Benevolent Association President Patrick Lynch said his union, which represents more than 50,000 active and retired NYPD officers, would “proceed with legal action to protect our members’ rights.” 

“From the beginning of the de Blasio administration's haphazard vaccine rollout, we have fought to make the vaccine available to every member who chooses it, while also protecting their right to make that personal medical decision in consultation with their own doctor,” Lynch said.

Detectives’ Endowment Association President Paul DiGiacomo also said his union, which represents thousands of active and retired NYPD detectives, would push back against the mandate. 

“The DEA was a fierce proponent of making the COVID vaccine available to Detectives so they can choose to get it. And as nearly 70% of members are vaccinated, it’s just that — a choice,” DiGiacomo said in a statement. 

“Our union will fight just as hard as we did to egnsure members could get the vaccine as we will to ensure they’re not mandated to do it,” he added. “The rights of every detective are our top priority.”

In his own statement, Henry Garrido, the executive director of the city's largest public employee union, DC37, said the mandate "must be collectively bargained and we expect City Hall to slow down and sit down with us," while noting that the union had "encourage[d] all our members to get vaccinated to protect themselves and their families."

Uniformed Firefighters Association President Andrew Ansbro, meanwhile, plans to hold a press conference to respond to the announcement at 3 p.m. on Wednesday. 

At his daily briefing Wednesday morning, de Blasio said he was not concerned about the unions' planned legal challenges. 

“I don’t anticipate legal issues. I’ve had this conversation with our corporation counsel… many times," he said. "We have seen, uniformly, courts agree and support vaccine mandates by governments, certainly by this government. State courts, federal courts, multiple reviews, every time came back the same way: the mandates were an appropriate way to protect employees and the people they serve."

The city will push the deadline back to Dec. 1 for a "small group" of uniformed correction officers who are not in health care settings. De Blasio said this is due to the "particular issues we’re facing on Rikers Island."

“We have a particular situation at Rikers, so what we said is, 'OK, if you work in the health care elements at Rikers, or in the hospitals related to Corrections, we need you vaccinated right away. If you’re a civilian employee, we need you vaccinated right away,'" he said. "We’re giving a few more weeks for the uniforms, because we’re in the process right now of bringing back a number of uniformed officers who weren’t present, and we’re in the process of intensely lowering the population, so we need to finish that out."

The Department of Correction had the lowest first-dose vaccination rate, 51%, of any city agency as of Tuesday, according to data provided by the mayor's office.

City workers who get vaccinated at city-run sites through Oct. 29 will receive an extra $500 in their paycheck as an incentive, according to the mayor. City employees without the shot will be placed on unpaid leave until they can show proof of vaccination.

Up until Wednesday, Department of Education employees were the only city workers required to be vaccinated. Workers at other city agencies have had the option to submit to weekly testing instead of getting vaccinated.