On April 21, 2026, Defense Secretary Pete Hegseth signed a memorandum ending the mandatory annual flu vaccine for all U.S. military service members — active duty, reserves, National Guard, and DoD civilians. The policy took effect immediately.
This is the seasonal influenza vaccine — the standard annual flu shot, not the COVID-19 vaccine (which was already rescinded in January 2023). Hegseth deliberately conflated the two, framing his decision as ending the Biden administration's “era of betrayal” and “unrelenting war on our warriors” — rhetoric about COVID applied to a completely unrelated, longstanding public health measure.
The military has required vaccinations since 1777, when George Washington ordered smallpox inoculations for the Continental Army. The DoD currently requires approximately 17 vaccines for service members. During WWI, the 1918 influenza pandemic killed approximately 43,000-45,000 American soldiers — nearly half of all U.S. military deaths and almost as many as the 53,402 who died in combat.
Military environments are uniquely vulnerable to flu outbreaks. Troops live in barracks, ship berths, and forward operating bases with extreme crowding. Historical outbreaks show attack rates of 10-20% in unvaccinated clusters. During the Vietnam War, bombing missions were temporarily suspended when air bases in Thailand were hit by the 1968 influenza pandemic.
This decision comes during an active war with Iran, with 50,000+ troops deployed to the Middle East and sailors already reporting food shortages and degrading conditions aboard ships. Making flu vaccination voluntary for troops in close quarters during wartime directly contradicts Hegseth's stated goal of “restoring strength to our joint force.”
Less than two months later, a flu outbreak hit Joint Base San Antonio-Lackland in Texas, sickening roughly 160 to 220 recruits with at least two hospitalizations, after the vaccination rate among recruits fell to about 40% from nearly 100%. The Air Force requested an exemption to require flu shots at the base and began vaccinating recruits. A recruit, Keon McDaniel, died on June 12 after a medical emergency during basic training, but officials have not said whether his death was linked to the flu, and that question remains under investigation. Rep. Joaquin Castro demanded answers.
On June 24, 2026, as the Lackland outbreak grew to roughly 275 sickened recruits, the Pentagon restored the flu-shot requirement for basic-training recruits only; Hegseth's broader policy making the shot optional for all troops remained in place. The Air Force had requested the exception on May 5; it was approved June 11, but Lackland officials did not learn the shots were mandatory again until June 18, by which point the outbreak was already underway.