In ongoing court fight, Boston argues employee vaccine mandate stands on solid legal ground

A recent order temporarily blocked the city from enforcing the requirement

Mayor Michelle Wu said she is committed to maintaining the vaccine mandate.Craig F. Walker/Globe Staff

In a court filing Tuesday, the city of Boston reiterated its stance that its vaccine mandate is on solid legal ground.

The city made its latest argument after a Massachusetts Appeals Court judge temporarily blocked its plans to require more than 18,000 employees be vaccinated against COVID-19, putting the policy on hold pending further legal review.

The city’s filing is the latest salvo in a legal and political drama that for now has blocked Mayor Michelle Wu from implementing what city officials describe as a crucial public health measure. The vaccine mandate, announced in December, was originally to take effect Jan. 15. But amid acrimonious disputes with labor unions, city officials delayed the start date twice, citing efforts to cooperate with unions and persuade more workers to be vaccinated and avoid being placed on unpaid leave. Now, the mandate’s future is uncertain as the city wages a contentious court battle with three first responders’ unions.

Some critics were furious when Wu in December tightened the city’s requirements, doing away with the option for city workers to take regular COVID tests in lieu of receiving the vaccine. Now, the fight has come to dominate the mayor’s early tenure, with protesters dogging her at public events and even appearing outside her home in the morning.

Wu has maintained she is committed to the mandate, saying it is essential to public health as the city continues to battle COVID-19. On Tuesday, she said the various restrictions the city has imposed against the pandemic are “not permanent.”

Responding to a reporter’s question about whether she might roll back mask or vaccine mandates in the near future, Wu said her team sets public health policy by closely tracking the city’s COVID-19 metrics and stays in “constant communication” with hospitals.

“COVID will be around for a while,” Wu said. “Even after we are through this surge, we know it is likely that next fall, next winter, there likely will be another surge. But in the meantime, as we’re tracking these numbers, these protections are not permanent. They are to make sure that we are safe in the most urgent moments, and we will continue to balance that guarantee of safety through public health policies that are responsive and clear, as well as the need to provide support to our small businesses.”

Three unions — Boston Firefighters Local 718, Boston Police Superior Officers Federation, and the Boston Police Detectives Benevolent Society — sued in late December to block the vaccine mandate, arguing that it would violate existing labor agreements. In January, a Suffolk Superior Court judge declined to block the mandate, citing “the public health emergency.” But after an appeal from the unions, a court last week put the vaccine mandate on hold pending further legal review.

Attorneys for Boston said the lower court was right to not keep the mandate from taking effect.

“The city will continue to work with its employees and unions to continue our progress towards a vaccinated workforce, which serves our important goals of protecting our colleagues and the public we serve,” a city spokesman said in a statement.

Travis Andersen of the Globe staff contributed to this report.