SAN JOSE — Nearly 50 San Jose patrol officers have COVID infections, a development that has prompted the police department to ask officers from other divisions to fill in, and a warning from the police chief that if the situation worsens, it could lead to a broader redeployment.

Police officers were informed of the fill-in plan late Saturday night by Chief Anthony Mata in an email obtained by this news organization, which outlined how patrols will have to be buoyed by voluntary overtime shifts at least through Sunday.

“Similar to other essential workers and first responders, COVID-19 has impacted our thinly staffed department and we are working through possible solutions to support our affected workforce,” Mata said in a follow-up statement Tuesday. “As always, our women and men are stepping up working extra shifts and ensuring an officer is there when you need one.”

The police department on Tuesday disclosed that 52 officers are currently sidelined by COVID-19. Of those infected officers, 45 are assigned to patrol. That has left the department hustling to meet its minimum patrol staffing level of 525 officers, which already accounts for nearly half of SJPD’s sworn staff.

In his weekend email, Mata emphasized how the department is “quickly approaching a critical point” and that officer safety is at risk “if we are unable to maintain minimum staffing levels in patrol.”

According to the city manager’s office, as of Dec. 7, 92% of sworn officers represented by the San Jose Police Officers’ Association were vaccinated, which amounts to 1,052 people. Information on how many have received booster doses is not available because boosters are not formally required for officers, though a mandate appears to be in the offing after a city council vote last week.

If fill-in shifts continue to be necessary to maintain patrol staffing in the longer term, Mata wrote in his email that as early as Jan. 24, the department could resort to requiring mandatory patrol shifts for officers in other areas. That could mean officers assigned to divisions like the detective bureau and special operations would have to devote a quarter of their work week to patrol.

The police department on Tuesday called the redeployment idea “a contingency plan we are working on to ensure patrol staffing levels remain where they should be.”

Union president Sean Pritchard said in a statement that the threat of a COVID-19 surge was something that could have been accounted for sooner, and that “one doesn’t need to be clairvoyant to have predicted this latest police staffing crisis” given the department’s thin personnel margins.

He endorsed the overtime shifts and warned about a domino effect that could come from reallocating specialized assignments.

“Deploying detectives to patrol is akin to robbing Peter to pay Paul; who will tell the rape or robbery or assault victims that they must wait longer for a resolution to their case?” Pritchard said.

The South Bay’s broader law-enforcement infrastructure is also seeing significant effects of the omicron wave. There were more than 250 active COVID-19 in-custody infections in the Santa Clara County jail system, which continues to surpass its records for the pandemic.

The San Jose Fire Department has avoided significant COVID-19 impacts, according to figures provided by the agency, which disclosed that 20 personnel were off duty because of the virus as of Tuesday. Spokesperson Erica Ray says the current infection rates in the department are lower than the winter surge of 2021. City data also shows that 94% of union-represented fire personnel are vaccinated.

Mata’s email and the contingency suggest a wait-and-see approach to the omicron wave and winter COVID-19 surge, which experts and at least one statistical model indicate could crest in California between the end of January and early February. A University of Washington model projects that more than half of the U.S. population will have been infected by omicron by the end of February.

Mayor Sam Liccardo said he felt confident that the infections in the police department will not substantially undermine the city’s ability to provide vital public-safety services.

“More officers are serving more overtime and we recognize that’s a necessary short-term strategy that will not be sustainable if we had a more sustained spike of infection. But based on what we know so far, we have every reason to believe this is temporary,” he said. “Given our high levels of vaccination I’d like to believe we’ll be beyond this in a couple of weeks.”

Liccardo added that the COVID-19 situation at SJPD is bolstering the case for a booster mandate.

“In any agency tasked with engaging with the public, we expect that infection will happen but the purpose of vaccination is to keep us all out of the hospital,” he said. “If we can get through this pandemic without any of our officers becoming seriously ill, that will be a great success.”

Staff writer Maggie Angst contributed to this report.