CHICAGO (CBS) — Mayor Lori Lightfoot won a major victory in her push to require all city employees to get COVID-19 vaccines, after an arbitrator ruled most city workers must get vaccinated.

The ruling, issued Wednesday, applies to city employees represented by several labor unions, including Chicago Firefighters Union Local 2, AFSCME, SEIU Local 73, IBEW Local 21, Teamsters Local 700, and all Coalition of Unionized Public Employees (COUPE) trade unions.

READ MORE: Chicago Weather Alert: Lake-Effect Snow On The Way With 6 To 8 Inches Possible In Some Areas; Winter Storm Warning Issued

The arbitrator’s ruling means employees in those unions must get their first dose of the COVID-19 vaccine by the end of the year. Employees who get either the Moderna or Pfizer vaccine must get their second dose by Jan. 31, 2022.

Employees who do not comply with the vaccine mandate can be put on no-pay status. All city employees may apply for a religious or medical exemption from the vaccine requirement.

“The City is pleased that a neutral arbitrator selected by both parties upheld the City’s right to issue a vaccine mandate to its employees,” Law Department spokeswoman Kristen Cabanban said in an email. “The arbitrator further upheld the City’s right to place employees who do not become vaccinated by the deadline in a no-pay status.”

Union representatives noted the arbitrator’s ruling allows employees who try to schedule their first shot by Dec. 31, but are unable to do so, will be allowed to present evidence to the city that they tried to meet the deadline, and ask for a short delay to get their first shot.

In addition, employees who sought a religious or medical exemption before Dec. 8 will be excused from the vaccination requirement until the city makes a decision on their request. Employees who are denied a religious or medical exemption will then be given six weeks to comply with the vaccine mandate.

The city also must have one further bargaining session with the unions by Dec. 27 to “resolve any issues that have been raised between the parties or as a result” of the arbitrator’s ruling, and the arbitrator still has jurisdiction to resolve any ambiguities or disputes arising from the decision.

READ MORE: Two Men Shot Dead In Car In Ravenswood; Car Goes On To Crash And Catch Fire

“While this is not the result we were hoping for, the Arbitrator’s decision does give us options to resolve further disputes created through the implementation of the policy,” Teamsters Local 700 said in a statement on its website. “As previously stated, Teamsters Local 700 maintains our position that individual members should be given the option of vaccination or regular testing. We will continue to take every action to protect members’ rights.”

SEIU Local 73 executive vice president Jeffrey Howard issued the following statement:

“Through our collective fight we have succeeded in obtaining additional time for workers to obtain the vaccination shots mandated by the city and we will continue to advocate for all of our members as the policy is implemented. SEIU Local 73 believes that getting vaccinated is the best thing our members can do to protect themselves, their families, and the people they serve.”

The ruling does not apply to the Chicago Fraternal Order of Police, the union representing rank-and-file police officers, and is awaiting separate arbitration on the vaccine mandate later this month.

Last month, a Cook County judge effectively put the vaccine mandate on hold for the city’s police unions, ruling the city could not fire or otherwise discipline police officers who don’t meet the vaccination deadline until the grievances that members of the city’s police unions file against the city are heard through arbitration.

All city employees already are required to report their vaccination status to the city through an online portal, or risk being put on no-pay status.

As of Monday, 95.63% of all city employees have reported their vaccination status. Of those, 81.2% have reported being fully vaccinated.

MORE NEWS: Pair Charged In Murder Of 8-Year-Old Melissa Ortega Denied Bail; Accused Teen Gunman Committed Three Previous Carjackings, Prosecutors Say

Every city department has reported at least 90% compliance with the vaccine reporting mandate, other than the City Council, which stands at 83.8% compliance.

CBS 2 Chicago Staff