NEW YORK (CBSNewYork) — The vaccine mandate deadline for all New York City workers to get their shots is now in effect.

The deadline was 5 p.m. Friday. That means starting Monday, employees who have not received at least one shot will be put on leave without pay.

READ MORE: FDNY Unions Protest Vaccine Mandate For NYC Workers, First Responders: ‘We Currently Have A Staffing Shortage As It Is’

Still, union leaders are fighting back.

As CBS2’s Aundrea Cline-Thomas reports, the city-run COVID vaccination site in Times Square was busier than usual Friday as the mandate deadline loomed for city workers.

“As we’re reaching this deadline we’re going to see a lot of what we saw with the Department of Education, with Health + Hospitals, that people do what’s necessary and get vaccinated,” he said.

Thousands of shots have been administered in the last 24 hours alone.

The FDNY saw a 5% jump in its vaccination rate in one day. The NYPD is at 84%, up from 80% Friday morning. EMS is at 84%, up from 77%. The Department of Sanitation had the biggest jump, now at 76% from 67%.

Those who don’t comply will be put on leave without pay, but there’s a loophole.

“We have a very growing population of vaccinated members of the NYPD. We also have a pretty significant population of people that have put in for accommodations,” NYPD Commissioner Dermot Shea said.

Those who asked for health and religious accommodations will keep working and continue with testing until their request is reviewed, which, in some cases, could just buy more time.

COVID VACCINE

Still, departments are putting the final touches on their contingency plans to deal with a possible shortage of first responders.

“We’ll be OK,” Shea said Friday morning. “The first step would be reassignment of personnel that ordinarily are not doing patrol functions can be pulled into those.”

The commissioner said the police force would also temporarily suspend training to free up additional bodies.

On Thursday, as the Police Benevolent Association filed an appeal to overturn a judge’s rule allowing the mandate to move forward, close to 1,000 more officers got the shot.

“A little better position today than we were let’s say a week ago,” Shea said.

As CBS2’s John Dias reports, the leader of Local 2507, which represents uniformed EMTs, paramedics and fire inspectors, said he’s proud of his workers, pointing out they are the lowest paid first responders.

“It’s been challenging for them to get the vaccine. Most of them work two jobs. Sometimes they do overtime all week to survive,” said Oren Barzilay, president of Local 2507. “They always work under challenging times, and they come through.”

Watch Aundrea Cline-Thomas’ report —

Among first responders, firefighters are some of the most resistant. Thousands protested Thursday outside Gracie Mansion.

Friday, a group of firefighters on duty were suspended for allegedly threatening state Sen. Zellnor Myrie’s staff in protest of the vaccine mandate.

READ MORE: NYC Vaccine Mandate: With FDNY, EMS Still Slow To Comply, There Are Real Concerns About Emergency Response Times

“While this was not the storming of the Capitol, all of us have reasons to be concerned when those who are entrusted with keeping us safe take the liberty to go to an elected official’s office and offer veiled and … an explicit threat of harm,” Myrie said.

The senator calls what happened at his Brooklyn office Friday morning a shameful display of disagreeing, shocked that on-duty FDNY members from Ladder 113 in Crown Heights, who are counted on as heroes, had the heart to harass his staff.

“Asked my staff where I live personally and followed up that inquiry with a statement along the lines of blood being on our hands come,” Myrie said.

While Myrie’s office has nothing to do with the city vaccine mandate, he believes the threats made to his staff were in protest of the rule.

In a statement, Fire Commissioner Daniel Nigro said, “This is a highly inappropriate act,” adding those involved “will face disciplinary action.”

They were suspended immediately.

“I’m speaking with the senator at the end of this press conference. I’ve asked for his number. I’d like to hear from him, and if apologies need to be made, they absolutely will be,” Uniformed Firefighters Association President Andrew Ansboro said Friday afternoon.

Myrie said he won’t take any legal action, but it’s his understanding more disciplinary action could be taken against the firefighters.

As CBS2’s Jessica Layton reports, the unions representing firefighters continue to insist they’re not anti-vaccine, but they are anti-mandate.

“We can’t even keep fire houses open today. New York City is going to come to a crisis on Monday morning. Response times are gonna go through the roof,” Ansboro said.

New York City Councilman Joe Borelli says already five fire houses in the Bronx and Upper Manhattan were closed Friday for staff shortages.

CBS2 has been told some firefighters are going on medical leave, which has led to companies temporarily out of service.

In response to that, Nigro said, “The excessive sick leave by a group of our firefighters because of their anger at the vaccine mandate is unacceptable, contrary to their oaths to serve and may endanger the lives of New Yorkers.”

The FDNY expects to operate some fire houses on a limited basis, about about 100 fewer ambulance tours per day.

New York Gov. Kathy Hochul says she will send state resources if needed.

“Whatever they need, we are going to make sure that the people in the city are protected. But also, the vaccination rates need to go up,” she told CBS2.

Canceling trainings and utilizing overtime are some of the ways the city plans to cover for any possible staff shortages come Monday when enforcement begins, but the spike in compliance in the eleventh hour, de Blasio says, makes some of those contingencies unnecessary.

“They can use overtime. They can turn to help from private entities if they need,” de Blasio said. “We feel very strongly we have the tools we need right now.”

Vaccine sites will be open over the weekend for those looking to get the shot last minute.

MORE NEWS: New York City Workers, Supporters March Across Brooklyn Bridge To Protest Approaching Vaccine Mandate

CBS2’s John Dias and Jessica Layton contributed to this report. Editor’s note: This story was first published Oct. 29.

Aundrea Cline-Thomas