The Pentagon has restored mandatory flu vaccinations for all military recruits, reversing a decision by Defense Secretary Pete Hegseth that made the shot optional in April. The move comes as a flu outbreak at the US Air Force’s boot camp at Lackland Air Force Base in San Antonio, Texas, has sickened nearly 300 people.
The outbreak, now roughly three weeks long, has produced 275 confirmed cases of the flu, according to Democratic Congressman Joaquin Castro, whose district includes part of the base. The base handles roughly 700 new recruits every week, and the close-quarters environment — with recruits sleeping together in large open rooms, showering communally, and conducting instruction in close contact — has long been recognized as conducive to the spread of disease.
Only 40% of the new trainees moving through the boot camp at Lackland opted to receive the flu shot once it became optional, according to a source familiar with the situation.
The Reversal
A Pentagon official confirmed the restoration of the mandate to the Associated Press, though the official maintained that the permission to mandate the vaccinations was unrelated to the Lackland outbreak. The official said the decision on exceptions to Hegseth’s April order was being finalized earlier in June, and the timing with the outbreak was just a coincidence.

When Hegseth first announced the repeal of the flu vaccine mandate in April, citing “medical autonomy” and religious freedom, he allowed the services to ask for exceptions — or permission to keep the vaccine mandatory — within 15 days of the rollout. Exceptions have now been granted to the Army, Navy, and Air Force, as well as the National Security Agency and the Defense Health Agency.
Expert and Advocacy Response
Arnold Monto, a flu expert and emeritus professor at the University of Michigan, said the new outbreak is “not unusually concerning,” but noted that “if you want to prevent flu outbreaks, it is especially necessary to vaccinate when there are group settings.”
Families Fighting Flu, an advocacy organization, cheered the restoration of the mandate. “For decades, the military prioritized the health and safety of troops and the public by requiring the flu vaccine for recruits. It’s unfortunate that more than 200 individuals at Lackland Air Force Base in Texas became ill when that requirement was rescinded,” said Michele Slafkosky, the organization’s executive director. “This updated guidance from the military will save lives.”
The Bottom Line
The Pentagon has restored mandatory flu vaccinations for all military recruits after an outbreak at Lackland Air Force Base in Texas sickened nearly 300 people. The mandate was reversed in April when Defense Secretary Pete Hegseth made the shot optional. Only 40% of recruits at Lackland had opted to receive the shot. Exceptions allowing the mandate have now been granted to the Army, Navy, and Air Force. The Pentagon maintains the restoration is not directly related to the outbreak but comes as it finalizes decisions on exceptions to Hegseth’s April order.





