The American Medical Association and more than 60 other health care associations on Thursday called on employers to voluntarily implement President Biden’s contested vaccine-or-testing mandate, saying businesses had no time to waste ahead of the busy holiday season.

“We — physicians, nurses and advanced practice clinicians, health experts, and health care professional societies — fully support the requirement that workers at companies with over 100 workers be vaccinated or tested,” the organizations wrote in a joint statement. “From the first day of this pandemic, businesses have wanted to vanquish this virus. Now is their chance to step up and show they are serious.”

The Occupational Safety and Health Administration issued the rule on Nov. 4, and the White House has said that the mandate will save lives by encouraging more people to get vaccinated. But Republican-aligned states, businesses and legal groups immediately sued to block it, arguing that it was government overreach, and a federal appeals court last week upheld a stay. OSHA has suspended enforcement of the rule, which was set to take partial effect on Dec. 5, pending further legal developments.

In Thursday’s joint statement, the health care associations said that Biden’s requirements for businesses were “reasonable and essential,” citing evidence that coronavirus outbreaks have been driven by viral spread at offices, retail locations and other business settings. “Requiring masks for all unvaccinated workers by the December 5th deadline will be key to keeping customers and fellow workers safe during the holiday shopping and travel season,” according to the organizations, which also include the American Academy of Pediatrics, the American College of Surgeons and the National League for Nursing.

The joint statement was coordinated by Ezekiel Emanuel, a bioethicist at the University of Pennsylvania who in July organized a similar effort to encourage health systems to require workers to get vaccinated. Emanuel said that the renewed push by medical groups is necessary because only 59 percent of Americans have received two doses of coronavirus vaccine and cases are on the upswing again.

“We’re not getting [enough] volunteers coming forward” to get vaccinated, Emanuel said, arguing that U.S. health workers have been “pushed to the limit” and are frustrated that millions of people remain unvaccinated. “We’re going to need mandates. And we know they’re effective.”

Coronavirus cases have risen about 17 percent and hospitalizations have risen about 4 percent in the past week, according to The Washington Post’s rolling seven-day average, with unvaccinated Americans far more likely to suffer severe symptoms and require medical treatment.

Several dozen health care experts also signed onto the joint statement, including Michelle Williams and Ashish Jha, the deans of Harvard University and Brown University’s public health schools, respectively; Eric Topol, director of the Scripps Research Translational Institute; former Centers for Disease Control and Prevention Director Thomas R. Frieden; and former White House coronavirus adviser Andy Slavitt.

The health care groups’ push conflicts with Republican-led efforts to blunt Biden’s vaccine-or-testing mandate. All 50 Senate Republicans on Wednesday filed a formal challenge through the Congressional Review Act, which allows Congress to overturn rules issued by federal agencies if a majority in both chambers oppose them. A congressional vote on the rule is expected in coming weeks.

“Biden’s ultimatum exacerbates issues faced by hard-working Americans by forcing workers to get jabbed or be fired,” Sen. Marsha Blackburn (R-Tenn.), who is helping lead the party’s challenge, said in a statement. “Republicans are unified in our opposition to President Biden’s abuse of power.”