The claim
“The U.S. military policy regarding the annual flu vaccine has been changed from mandatory to optional.”
This claim was made by Pete Hegseth on 2 October 2026, in relation to a report by ABC News regarding a flu outbreak at Joint Base San Antonio.
Our verdict
True
The claim is true. Secretary of War Pete Hegseth officially changed the long-standing military policy to make the annual flu vaccine optional for service members.
What we found
In April 2026, Secretary of War Pete Hegseth signed a memorandum that removed the mandatory requirement for the annual flu vaccine, which had been in place since 1945. Official records from the Department of War confirm that the policy was shifted to make the vaccination voluntary.
Following this change, reports from multiple news outlets, including the New York Times and ABC News, documented a significant influenza outbreak among Air Force recruits at Lackland Air Force Base. Due to the scale of the outbreak, the Pentagon subsequently granted exceptions to allow the Air Force to resume mandatory vaccinations for trainees.
The evidence
5 of 6 sources support the claim; none contradict it.
- Supports the claim
Secretary of War Pete Hegseth issued a memorandum making the annual flu vaccine optional for military personnel, replacing a previous mandatory requirement.
war.gov· Hegseth: Flu Vaccine Optional - Supports the claim
A flu outbreak occurred among Air Force recruits at Joint Base San Antonio following the shift to an optional vaccine policy.
abcnews.com· Flu outbreak among Air Force recruits at Joint Base San Antonio after Hegseth ends mandatory flu vaccine - Supports the claim
Following the policy change, a flu outbreak occurred at Lackland AFB, leading the Pentagon to grant exceptions allowing the Air Force to resume mandatory vaccinations for trainees.
militarytimes.com· In shift, Pentagon grants flu vaccine exceptions to military services, some federal agenciesJune 24, 2026
- Supports the claim
A flu outbreak occurred at Lackland Air Force Base following the policy change, resulting in over 200 illnesses.
theconversation.com· The military traded its flu vaccine mandate for ‘medical freedom’ – an outbreak quickly followed - Supports the claim
A flu outbreak occurred at Lackland Air Force Base following the removal of the vaccine mandate.
nytimes.com· Scores Fall Ill at Air Force Base After Hegseth Makes Flu Vaccine OptionalJune 18, 2026
- Background
Pete Hegseth announced a policy change making the flu vaccine optional, reversing a mandate dating to 1945.
abcnews.com· Military services again requiring recruits to get flu shots as Air Force outbreak growsJune 24, 2026
What we could not confirm
- The exact date in April 2026 when the memorandum was signed is not specified in official records.
- The precise number of recruits affected by the outbreak varies between reports, ranging from 159 to over 200 cases.
- While the outbreak followed the policy change, a direct clinical causal link between the two events has not been formally established.
How we checked
We reviewed official Department of War policy announcements and cross-referenced these with reports from multiple news organisations covering the subsequent health developments at military facilities. We reviewed 8 relevant sources.
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