Health experts are hoping the effects of new Pentagon policy are minimal following Defense Secretary Pete Hegseth’s directive to make flu vaccines optional rather than required.
Hegseth made the announcement on Tuesday, saying in an X post that the decision not to force annual flu shots was based on “freedom” and “effective immediately.” The secretary signed a memorandum the same day making the annual influenza vaccine voluntary for all active and reserve component service members, as well as Defense Department civilian personnel.
"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. "Our new policy is simple: If you, an American warrior entrusted to defend this nation, believe that the flu vaccine is in your best interest, then you are free to take it; you should. But we will not force you."
Influenza symptoms may include high fever, chills, severe muscle or body aches, fatigue, cough and sore throat—all of which tend to appear usually 1–4 days after exposure. From there, it could either fade after a couple days or continue for roughly two weeks.
It’s a sea change in the ranks, as vaccines have been required for U.S. service members dating back to the 1950s. Research cited by the National Institute of Health shows that in the first 175 years or so of the nation’s history, more military personnel succumbed to illness rather than via the effects of war itself.
The most frequent diseases that led to service members’ deaths were dysentery, typhoid fever, malaria and yellow fever, and respiratory illnesses including measles, pneumonia and influenza.
It’s estimated that of the 500,000–600,000 soldiers who died of disease during the U.S. Civil War, about 95,000 deaths were attributed to dysentery.
In both the Mexican-American and Spanish-American wars, roughly seven soldiers died of disease for every one killed in combat. After approximately 45,000 U.S. soldiers died of flu during World War I, vaccines widely available by World War II helped reverse longstanding domestic trends.
Timing of Decision
The move, according to health experts, continues a looser vaccine stance by the Trump administration—beginning with vaccine pushback during the COVID-19 pandemic and extending to the present, through Health and Human Services directives and now the Defense Department.
Georges Benjamin, CEO of the American Public Health Association, told Military.com it is “an irresponsible decision that will undermine the medical readiness of our troops.”
He feels strongly about the issue because he is familiar with it.
He is a former military physician who trained in the U.S. Army and was ER director for four years at Walter Reed Army Medical Center. He also served on the public health advisory committee of the Defense Health Board.
“If you go back and look at the 1918 influenza, when we didn't know what it was, it had a devastating impact on our troops,” Benjamin said. “We know what flu does to troops who are quartered closely together, who share food, who share rooms, and contagious diseases like influenza can put a whole unit out of service.
“So, there's no question that not only is it a significant health issue, but it's also a significant readiness issue. It impacts our troops not only in their preparation for fighting, but also once they're in the field. Influenza is not a disease that you want to get in the middle of a firefight.”
Josh Michaud, associate director for global and public health policy at KFF, said he wasn’t necessarily surprised when he heard of the new DOD policy considering the varied medical guidance that has been issued within the Trump administration—through HHS and the CDC, for example.
“It really represents a big change and a policy that's been in place for such a long time,” Michaud told Military.com, adding that considering the influenza vaccine’s customary place in the U.S. military dating back to the 1950s, it further exemplifies the administration’s intent to give individuals choice.
COVID Impact and Medical Autonomy
Between Aug. 24, 2021, and Jan. 10, 2023, military personnel were required to get the COVID-19 vaccine. Ultimately, more than 8,000 service members were involuntarily discharged for their refusal to do so. Many were later reinstated.
“It erupted a lot of people the wrong way and was an example in many people's minds of government overreach, or the imposition on people's freedoms of choice when it comes to deciding their own health,” Michaud said. “So, it fed into an already existing vaccine hesitancy, or people having questions about vaccines that had been lingering for decades.
“It opened the door for a different approach by the Trump administration, definitely compared to the Biden administration, but also many other previous administrations, which have been strongly, broadly supportive of vaccines, to placing a higher priority on this idea of individual health choice or health freedom.”
While acknowledging that influenza’s effects most often impact the elderly or younger people with immune diseases, Michaud said that cases of influenza could still negatively affect military units or constellations due how it spreads.
“Influenza can be a debilitating disease and it can, in the short term, cause people to be bedridden or unable to function normally,” he said. “That can have an impact, maybe 15% of a given population may be infected with influenza in a given year and experience a spectrum of different illnesses.
“It's hard to quantify the potential impact that this could have, but certainly it could lead to people missing work or not showing up, or having to request time off to recuperate from influenza infections that otherwise might not have happened.”
But medical and other exemptions for religious beliefs, for example, have always existed in the military ranks, said Angela Shen, adjunct professor at the University of Pennsylvania's Perelman School of Medicine.
Shen, a retired captain in the U.S. Public Health Service who held leadership roles in HHS, CDC and the FDA, told Military.com that she has three clear recommendations for certain groups to vaccinate: college kids in congregate settings like dorms, the elderly in shared living spaces, and military personnel in close quarters.
There's a reason why most schools, colleges, daycares and even some workplaces require vaccinations, she added.
"The flu shot protects the soldier as much as the unit," Shen said. "If a soldier gets sick, the unit tends to get sick. ... Mandates are evidence-based strategies that lead to higher vaccination coverage. You can reach the threshold for herd immunity, but you need to have a high enough number for herd community to work."
Effects on Military Readiness
Benjamin said the makeup of the U.S. military doesn’t necessarily jive with an ideology that puts personal freedoms above the larger population, including from a functional operations standpoint.
“We put people in harm's way in a variety of situations, right?” Benjamin said. “We don't tell troops that they can make a decision about charging the hill. We do have conscious objectors, we do find ways to work around that. But in general, we don't do that.”
He wondered what would happen if multiple personnel decided against vaccinating, how it would impact colleagues. He provided the example of flu spreading on a nuclear submarine, where individuals in close quarters may be stuck underwater for days or weeks at a time without reprieve.
“I mean, this is part of the job,” he said. “This is being fit. We're requiring them to maintain ideal body weight. We're requiring them to do all kinds of things to maintain their readiness. We hold commanders responsible if their troops get heat-related injuries."
“Every primary responsibility is being part of the front and fighting with a weapon," he added.
Shen also disagreed with the sentiment that medical autonomy helps rather than hurts the military.
"It kind of comes out of the same playbook," Shen said. "If the overarching theme is about choice and personal freedom, then all falls under the topic sentence. Everything they can control, they'll make a policy off that. ... [Illness] doesn't just affect you, it affects those around you. Your individual freedom is infringing on me."
