Military flu shots mandatory again after 300 people get sick at boot camp: report

The Pentagon will once again require flu shots for all military recruits after a weekslong flu outbreak sickened hundreds of people at Lackland Air Force Base boot camp in San Antonio, Texas, according to The Associated Press. 

Sources told the AP that although nearly 300 people were ill, the return of mandatory flu vaccines is not tied to the outbreak. 

Military reverses course on flu shots

The backstory:

Defense Secretary Pete Hegseth announced in April that flu shots would no longer be mandatory in the military. He cited "medical autonomy" and religious freedom, but the new policy did allow military branches to ask for exceptions that would keep the vaccine mandatory. 

Officials told the AP that a decision on those exceptions was being finalized earlier this month. The flu outbreak at the Texas military base was a coincidence, the official said. 

Sean Parnell, a Pentagon spokesman, confirmed that exceptions were granted to the Army, Navy, and Air Force as well as the National Security Agency and the Defense Health Agency. Parnell declined to give more details. 

By the numbers:

The Lackland base handles roughly 700 new recruits every week, according to Air Force figures. There were 275 confirmed flu cases at Lackland, according to Democratic Rep. Joaquin Castro. Only 40% of the new recruits at Lackland got a flu shot once it became optional, a source told the Associated Press.

Dig deeper:

Living in close quarters is one reason why the flu spread so fast at the Air Force base. Recruits are exposed to high stress, low sleep, and close contact conditions for weeks. They typically sleep together in large, open rooms, shower communally, and conduct much of their instruction and inspections in close contact.

READ MORE: New Air Force One delivered to Joint Base Andrews

Although flu activity is higher in the late fall and winter, outbreaks can happen in spring and summer, especially on military bases, cruise ships and other settings where a lot of people are gathered together indoors, Dr. Arnold Monto, a flu expert and emeritus professor at the University of Michigan, told the AP. 

What you can do:

Monto said flu shots are "especially necessary" to prevent outbreaks in group settings. 

What they're saying:

"This updated guidance from the military will save lives," Michele Slafkosky, executive director of Families Fighting Flu, an advocacy organization, said in a statement.