PHILADELPHIA — Philadelphia’s vaccine mandate for city employees, which was supposed to take effect Friday, has been delayed to Jan. 24 due to a new agreement between Mayor Jim Kenney’s administration and the union for white-collar city workers.

The mandate, announced in November, will require all 22,000 unionized city employees to show proof of vaccination or obtain for an exemption for religious or medical reasons. If they fail to do so, workers will be placed on administrative leave for 15 days, and, if they have not begun getting vaccinated by the end of that period, they will be fired.

But no municipal employees are getting fired for failing to comply with the mandate anytime soon.

After the policy was announced, the city’s four major unions sought negotiated agreements or labor arbitration rulings, largely over details of the mandate’s implementation such as how the city would evaluate exemption applications and how sick days would be counted for people who take time off while dealing with a reaction to the vaccine.

The city on Friday announced that it had reached an agreement with the American Federation of State, County and Municipal Employees District Council 47, which represents white-collar workers including administrative assistants and health care professionals, that resets the deadline for their members to become vaccinated to Jan. 24.

The city’s largest union, AFSCME D.C. 33, which represents blue-collar workers such as trash collectors, had already agreed to comply with the mandate by Friday. But the labor arbitration award that set that deadline also included a provision in which D.C. 33 members are entitled to a later deadline if any other union negotiates a different date.

The other two major municipal unions, the Fraternal Order of Police Lodge 5 and the International Association of Fire Fighters Local 22, are still in arbitration proceedings. It’s possible that the deadline for the mandate could be pushed back even further if their arbitration awards set a date past Jan. 24.

The city’s 3,200 nonunion employees are already subject to a vaccine mandate that took effect Dec. 1, and the mayor’s office has said almost 99% of those workers are in compliance.