More than 150 troops at Lackland Air Force Base in Texas have been infected with influenza over the past three weeks — a major outbreak less than two months after Defense Secretary Pete Hegseth said American troops would no longer be required to be vaccinated against the flu.
The Air Force said in a statement Thursday that the 37th Training Wing, which is at Lackland, “has been managing a localized influenza outbreak among trainees at Basic Military Training.”
About 160 people have become ill, according to two people familiar with the matter who spoke on the condition of anonymity because of the sensitivity of the issue. More than 36,000 military recruits come through the 37th Training Wing each year.
The Air Force did not immediately respond to a question about whether the troops who contracted the flu had been vaccinated. The outbreak was first reported by the New York Times.
People showing symptoms are being isolated and treated, and medical personnel are also monitoring those who were in close contact with sick individuals, according to the Air Force statement. Recruits will return to training once they’re cleared by medical staff.
The Air Force also said in a news release earlier this week that Keon McDaniel, who was in his sixth week of basic military training, died after experiencing a medical emergency and being transported to nearby Brooke Army Medical Center. The Air Force is investigating whether his death is related to the outbreak, but that review is still underway, a U.S. official said, speaking on the condition of anonymity because of the sensitivity of the issue.
In April, Hegseth announced he would be rolling back a decades-old mandate requiring U.S. troops to receive the annual flu vaccine. The defense secretary called the requirement “overly broad” and said that soldiers would be able to take the vaccine if they believed it was in their best interest, describing it as an effort to “restore freedom and strength to our joint force.”
Chief Pentagon spokesperson Sean Parnell said Thursday in a statement that the Department of the Army, Department of the Navy, Department of the Air Force, National Security Agency, and Defense Health Agency had been granted permission to require the vaccines in certain circumstances.
“The decisions were based upon thorough risk assessments and are designed to maximize operational readiness, lethality, and force generation, while safeguarding at-risk populations,” Parnell said, adding that the military components requesting the exceptions are responsible for their implementation.
Undersecretary of Defense for Personnel and Readiness Anthony Tata told members of Congress last month that the Pentagon was reviewing exceptions for service members in environments such as basic training, submarines, ships, and Army Ranger School.
The Times reported Thursday that in the midst of the recent outbreak, the Air Force was granted an exception to the new voluntary vaccine policy, requiring that recruits at Lackland get flu shots. The Air Force did not immediately respond to questions from the Washington Post about whether that exception had been put in place.
Influenza rates are considered low right now nationally and in Texas, according to tracking by the Centers for Disease Control and Prevention and the Texas state health department. But living in close quarters could exacerbate an outbreak, as flu is spread mainly when people cough, sneeze, or talk.
The flu vaccine is not a cure-all; it is much less effective in preventing infections than vaccines such as the one for measles, mumps, and rubella, which the CDC says prevents measles in about 97% of cases when patients have received two doses. But multiple studies have shown the flu vaccine reduces the disease’s severity and averts hospitalizations and deaths.
However, Health Secretary Robert F. Kennedy Jr. has a long history of disparaging vaccines. As health secretary, he stopped a flu awareness campaign and downgraded the recommendation for childhood shots.
The U.S. military first mandated the flu vaccine in 1945, at the end of World War II — in part to hedge against the threat of biological warfare and because the influenza pandemic of 1918 to 1920 had hindered American troop readiness during World War I, killing more than 26,000 American soldiers. The mandate was briefly withdrawn in 1949 but reinstated in the 1950s.
Military vaccine mandates were a campaign issue for President Donald Trump, who promised during his 2024 campaign to rehire individuals who had lost their jobs over the military’s requirement that service members be vaccinated against the coronavirus.
“I will rehire every patriot who was fired from the military with an apology and with backpay,” Trump said at the time, which he went on to do in an executive order in January last year.


