In April, Secretary of Defense Pete Hegseth changed Pentagon policy to make flu shots voluntary for all military personnel, declaring that mandatory influenza vaccines "weaken our war-fighting capabilities." Within weeks, recruits at Lackland Air Force Base in San Antonio started getting sick.
The virus burned through boot camp, and by June 24th, according to a statement from Congressman Joaquin Castro, 275 people had been infected. The Air Force confirmed one trainee died June 12th due to a medical emergency, though officials did not specify whether it was flu-related.
The speed with which it all happened was not a surprise to Dr. Luis Ostrosky, chief of infectious diseases at UT Health Houston. He said the April policy change created an "epidemiological time bomb."
"Military settings are prime for transmission,” Ostrosky said. “When you have an introduction of a highly communicable disease in a congregate setting like this, it's just going to spread like wildfire."
Secretary Hegseth argued the voluntary policy would pose no threat to military readiness. But Ostrosky said the outbreak demonstrates the opposite. He explained that even young, otherwise healthy recruits can be bedridden for days or hospitalized with influenza.
"It ends up affecting our readiness for combat at a time when we're having several conflicts throughout the world," he said.
San Antonio Mayor Gina Ortiz Jones, a Democrat who previously served as Undersecretary of the Air Force, drew a direct line between Hegseth's decision and the outbreak at her city's base.
"Regardless of whether you want to believe it, science is a thing," Jones said. "It's really unfortunate that we're playing politics with people's public health and with things like vaccines."
Just 40 percent of Lackland’s spring trainees chose to receive a flu shot once it became optional, according to the Associated Press, quoting a source who asked to be anonymous because the information is not public.
But Ostrosky doesn’t blame the plunge in uptake on the troops. He said it was driven by the broader climate of medical misinformation. He said recruits were unsure whether vaccines work, were worried about side effects, and were in an environment of deep mistrust in public health institutions.
In mid-June, the Pentagon partially reversed course, granting all service branches the authority to once again mandate flu vaccines for trainees. The shots remain voluntary for all other troops. A Pentagon statement said the decision was aimed at maximizing "operational readiness while safeguarding at-risk populations."
Ostrosky welcomed the change as a good first step, but called for mandatory flu shots for all active-duty personnel.
"The vaccination schedules that had been in place in the military are the result of decades of actual research and very deliberate thinking and creating guidelines," Ostrosky said.
More exceptions may be on the way. Army and Navy officials have separately requested Pentagon permission to mandate flu shots for troops deploying overseas, as well as for healthcare and childcare workers, according to the AP.
This story was produced by the American Homefront Project, a public media collaboration that reports on American military life and veterans.
