For hundreds of public employees in the state of Washington — where a new vaccine mandate for state employees went into effect this week — Monday was their last day on the job. That includes a sergeant with the Washington State Patrol who told KUOW that he had made an appointment to turn in his patrol car and equipment .

In Los Angeles County, Sheriff Alex Villanueva announced earlier this month that he would not carry out the county's mandate for his department's 18,000 employees, warning that the nation's most populous county could lose "5, 10% of my workforce overnight."

And in Chicago, the clash between police and city officials over the city's vaccine mandate has grown so contentious that a judge ordered the local union president to stop making public statements after the city's attorney accused him of "municipal sedition and treason."

As vaccine mandates for public employees begin to take effect across the country, police officers and the unions who represent them are putting up a fight, frustrating officials who say their goal is to minimize deaths as the COVID-19 pandemic drags on.

"More police officers die of COVID than they do in other causes of death, so it doesn't make any sense to not try to protect yourself as well as the colleagues that you work with," Dr. Anthony Fauci, the nation's top infectious disease official, said in an interview on Fox News Sunday.

More than 230 police officers in the U.S. have died of COVID-19 so far in 2021, more than quadruple the number of deaths by gunfire, according to the Officer Down Memorial Page, a group that tracks on-duty police deaths. Last year, coronavirus killed nearly 250 officers nationwide, including four in Chicago .

"I want to make sure that our officers who are literally working their tails off every single day, risking life and limb, are absolutely able to take advantage of this life-saving vaccine," said Chicago Mayor Lori Lightfoot in a press conference on Monday.

As of Monday, 79% of all city employees had complied with Lightfoot's order to submit their vaccination status, officials said. But about a third of employees in the Chicago police department — more than 4,500 total, including sworn officers and civilian employees — refused.

The city's Fraternal Order of Police, led by its president John Catanzara, had repeatedly encouraged officers to not comply with the city's requirement that all municipal employees share their vaccination status by last Friday's midnight deadline. That led to his admonishment by a judge Friday.

Employees who do not report their status, including police officers, will not be paid, the mayor said Monday. According to WBEZ , an internal memo sent over the weekend warned department employees that if they do not comply with the policy, they could be fired.

More than 20 states have implemented some form of vaccine mandate for state employees, and many major municipalities have put them in place as well.

Vaccine mandates are effective at getting people vaccinated, which in turn reduces serious illness and death from COVID-19. Major companies like United Airlines and Tyson Foods announced mandates and have since reported that the vast majority of their employees are vaccinated. In Washington, Gov. Jay Inslee said last week that more than 90% of state workers have been vaccinated.

But police officers have consistently resisted the vaccine at higher rates than the general public. Combined with rising levels of crime — violent crime was up about 5% overall in 2020, with murders up nearly 30% — police unions have begun to raise concerns that tough enforcement of the mandates could result in staffing shortages.

In Seattle, detectives and other non-patrol officers were dispatched to emergency calls last week, according to local TV station KOMO .

In Massachusetts, where Gov. Charlie Baker's vaccine mandate took effect Monday, at least 150 state police officers have resigned or submitted paperwork to do so, according to the union, though the state has not yet confirmed those numbers. Roughly 85% of state police officers are vaccinated, but union officials say the resignations are exacerbating an already difficult staffing situation.

"Critically low staffing is the single largest threat to public safety today," said Michael Cherven, president of the State Police Association of Massachusetts, at a press conference on Monday. "We are in dire need of courageous leadership that places public safety above politics."

Across the country, opponents have filed lawsuits hoping to block the vaccine mandates, but there's a long history of them passing legal muster.

Many of the suits have already been rejected by judges, including the Supreme Court declining emergency appeals by teachers in New York City and university students in Indiana .

Copyright 2021 NPR. To see more, visit https://www.npr.org.