An Air Force trainee at the Lackland Air Force Base in San Antonio, Texas, died from the flu after Defense Secretary Pete Hegseth axed mandatory vaccine requirements.

Keon Talik McDaniel, 25, died June 16, according to his obituary. McDaniel was in his sixth week of basic military training when he experienced a “medical emergency” on June 12. He was taken to Brooke Army Medical Center, where he died days later, the Air Force said.

McDaniel’s cause of death was influenza, Texas Democratic Rep. Joaquin Castro said in a statement.

“The Air Force confirmed that trainee Keon McDaniel died from the flu during the outbreak at Lackland Air Force Base in San Antonio,” Castro said. “This is a tragedy that could have been prevented were it not for the reckless actions of Secretary Hegseth….Our military must be guided by science, not politics.”

In April, Hegseth announced that the U.S. military will no longer require all American troops to get the flu vaccine, citing “medical autonomy” and religious freedom.

“The notion that a flu vaccine must be mandatory for every service member, everywhere, in every circumstance at all times is just overly broad and not rational,” Hegseth said in a video posted on social media.

He said service members are free to get the flu vaccine but will not be forced to “because your body, your faith and your convictions are not negotiable.”

With the shot now voluntary, the vaccination rate for recruits at Lackland plummeted from nearly 100% to about 40%. Over the past month, the influenza outbreak at Lackland sickened nearly 300 recruits, resulting in several hospitalizations.

In response to the rapidly spreading virus in the close quarters of the barracks, Hegseth reinstated the mandatory vaccine requirement and rushed to vaccinate troops, according to The Guardian.

Castro argued that Hegseth undermined military readiness by axing the flu vaccine mandate.

Castro and Rep. Chrissy Houlahan (D-Pa.) co-sponsored an amendment to the National Defense Authorization Act (NDAA) to require military servicemembers to be vaccinated for influenza. But House Republicans rejected the amendment last week.

“When our troops volunteer to risk their lives for our country, the least we can do is not ask them to risk their lives because their leaders abandoned decades of military medicine,” Rep. Houlahan said. “The House Rules Committee’s refusal to make our amendment in order was a missed opportunity to right Secretary Hegseth’s wrong and to put military readiness ahead of politics. We owe our servicemembers better.”