SAN ANTONIO, TEXAS — An influenza outbreak has sickened at least 159 recruits at Lackland Air Force Base in San Antonio, Texas. The outbreak follows Defense Secretary Pete Hegseth's decision in April to end the mandatory influenza vaccine requirement for military personnel.

Hegseth stated, "We're seizing this moment to discard any absurd overreaching mandates that only weaken our war fighting capabilities. In this case that includes the universal flu vaccine and the mandate behind it. Your body, your faith and your convictions are not negotiable." After the mandate was rescinded, approximately 40% of Air Force trainees opted to receive the influenza vaccine.

As a containment measure, Air Force officials at the base ordered recruits to receive influenza vaccinations. The 37th Training Wing implemented isolation and treatment protocols for trainees showing influenza symptoms. These symptomatic trainees are receiving antiviral medications, including Tamiflu.

The base is part of Joint Base San Antonio, an installation that houses approximately 70,000 personnel. Recruits at the base live in communal dormitories and dine in shared facilities.

The Under Secretary of Defense for Personnel and Readiness authorized exceptions to the influenza vaccine mandate for the Army, Navy, Air Force, National Security Agency, and Defense Health Agency when operational requirements necessitate such action.

Chief Pentagon Spokesman Sean Parnell said, "The decisions were based upon thorough risk assessments and are designed to maximize operational readiness, lethality, and force generation, while safeguarding at-risk populations." In the 2025-2026 season, about 46% of U.S. adults were vaccinated against influenza, according to the Centers for Disease Control and Prevention.