(CNN) Justice Department lawyers have determined that federal law doesn't prohibit public agencies and private businesses from requiring Covid-19 vaccines -- even if the vaccines have only emergency use authorization, according to an opinion posted online Monday.
The opinion from the department's Office of Legal Counsel paves the way for more federal agencies and businesses to require vaccinations.
The Department of Veterans Affairs announced on Monday that it will require many of its front-line health care workers to be vaccinated against Covid. The VA is the first in the federal government to require shots among its workers.
Some colleges, both public and private, are requiring their students to get vaccinated before returning this fall. Governments -- particularly the state of California and New York City -- are also previewing plans to require vaccines for certain public workers.
So far, opponents of vaccine mandates haven't had much luck in court when challenging the requirements.
In June, a federal judge sided with a Houston hospital when employees sued to block its Covid-19 vaccine requirement. A federal court also rejected this month a request by students that it block Indiana University's vaccine requirement.
In recent weeks, Justice Department officials have been weighing requests from private businesses and federal agencies seeking legal backing for policies aimed at encouraging vaccinations, according to people briefed on the matter.
The opinion posted on Monday marks a shift from the Trump administration. Last year, Attorney General William Barr used the Justice Department's legal power to try to fight certain Covid restrictions.
In its vaccine mandate opinion, which was dated July 6, the department's Office of Legal Counsel said that the law around so-called emergency use authorizations addresses the obligation that certain information be passed on to potential vaccine recipients. The law "does not prohibit public or private entities from imposing vaccination requirements for vaccines that are subject to EUAs," the opinion said.
Nicholas Bagley, a University of Michigan law professor who specializes in administrative and health care law, told CNN in an email that the Justice Department had offered a "good legal analysis." But he was skeptical of the impact the opinion would have. The weaknesses in the legal arguments against vaccine mandates have "been apparent for a long time now," Bagley said.
"If we see institutions change their minds about vaccine mandates, I suspect it'll have more to do with the way that risks associated with Delta have changed the assessment of the value of those mandates," Bagley said, referring to the Covid variant that is propelling a surge in cases among unvaccinated individuals.