The U.S. Army, Navy, and Air Force have reinstated mandatory influenza vaccinations for new recruits, reversing a policy change implemented earlier this year by Defense Secretary Pete Hegseth after military health officials linked the absence of flu immunization requirements to outbreaks at several training facilities.
The decision marks one of the first significant public reversals of a health policy adopted under Hegseth's leadership and comes after concerns that respiratory illnesses were affecting military readiness during basic training.
According to ABC News, all three military branches have resumed requiring flu vaccinations for recruits entering basic training programs. The policy change follows months of growing concern among military medical officials over the spread of influenza among new service members living and training in close quarters. The Marine Corps had continued requiring flu shots and was not affected by the earlier policy change.
In March, Hegseth suspended the longstanding requirement that recruits receive influenza vaccinations during initial military training.
The Pentagon argued at the time that the move would increase medical choice among service members and reduce mandatory vaccination requirements. The decision was welcomed by some critics of military vaccine mandates but immediately drew concern from military health experts, who warned that training camps historically have been especially vulnerable to respiratory disease outbreaks.
For decades, the military has treated influenza as a readiness issue because recruits live in barracks, eat together and conduct training in close physical proximity, conditions that can rapidly spread infectious diseases.
The policy came under scrutiny after outbreaks were reported at several military training installations.
One of the most significant incidents occurred at Joint Base San Antonio-Lackland in Texas, home to Air Force basic training. Hundreds of trainees reportedly contracted influenza during the spring training cycle.
Military officials also investigated additional outbreaks at Army and Navy training facilities, raising fears that illness-related absences could disrupt training schedules and delay graduation timelines.
Health experts pointed to historical evidence supporting vaccination programs in military populations. Influenza has long been recognized as a recurring threat in recruit training environments because of crowded living conditions and the constant arrival of new personnel from across the country.
The concerns intensified after a respiratory illness outbreak at Lackland Air Force Base was linked to at least one recruit death and numerous hospitalizations, prompting renewed calls from military physicians to restore preventative vaccination measures.
A Long Military History With Flu Vaccines
The military has required influenza vaccinations for most service members for decades.
According to the Department of Defense, annual flu vaccination programs have traditionally achieved some of the highest vaccination rates in the country. Military health officials have consistently argued that preventing outbreaks is critical because widespread illness can quickly affect operational readiness.
The requirement dates back to lessons learned during the 1918 influenza pandemic, which killed thousands of military personnel and disrupted troop deployments during World War I.
More recently, flu vaccination programs have been credited with reducing outbreaks during training cycles and limiting lost training days.
Military epidemiologists have repeatedly found that recruits face higher infection risks than the general population because of communal living arrangements, shared facilities and intensive physical activity that can temporarily weaken immune responses.
The decision to restore the mandate has generated mixed reactions.
Supporters argue the move reflects evidence-based public health policy and a recognition that military readiness depends on preventing avoidable illness.
Former Pentagon officials and military physicians largely welcomed the reversal, saying influenza vaccination is one of the simplest and most effective tools available to protect recruits.
Legal analyst Ryan Goodman, a former Defense Department official, described the reversal as a correction of an "ill-fated policy," arguing that military leaders should prioritize force health protection over ideological debates.
The reinstated requirement will apply to incoming recruits in the Army, Navy and Air Force.Military officials have indicated they will continue monitoring respiratory illnesses at training installations and may review other health protocols if outbreaks persist.
