Is the ‘Man Flu’ Actually Real?

Maybe, maybe not.

Photo Illustration by Lyne Lucien/The Daily Beast

’Tis the season: for sneezes, itchy watery eyes, coughing—and whiny dudes who can’t seem to suck it up and deal with the fact that yes, they are dealing with the flu.

According to a paper published Tuesday in the journal BMJ’s famously eccentric Christmas issue, those XY-chromosomed humans swearing that their flu is indeed worse than those of females should maybe be believed.


Kyle Sue, a clinical assistant professor in family medicine at Memorial University of Newfoundland in Canada, argues in the paper titled “The Science Behind ‘Man Flu,’” that the term “man flu”—the idea that men suffer more harshly from the flu than women—had been something that hadn’t faced any medical scrutiny. “Despite the universally high incidence and prevalence of viral respiratory illnesses, no scientific review has examined whether the term ‘man flu’ is appropriately defined or just an ingrained pejorative term with no scientific basis,” Sue wrote. “Tired of being accused of over-reacting, I searched the available evidence to determine whether men really experience worse symptoms and whether this could have any evolutionary basis.”

So Sue went on a quest to figure out if the “man flu” exists. He reviewed—and this is incredibly important—already published articles on various medical research databases such as Google Scholar and PubMed/MedLine and searched for terms such as “man/male,” “woman/female,” “gender,” “flu,” and more.

It’s been well established in the medical literature among mice and men that males tend to have weaker immune systems than females, and that their response to respiratory infections are harsher than women. Women are more responsive to the flu vaccine than men, with a study going so far as to say that testosterone blocked antibodies from the vaccination; estrogen, on the other hand, forms a sort of protective shield over cells that might be vulnerable to the flu. That logic, Sue argued, can be carried over to the “man flu” and traced back to the evolutionary need for men to preserve their energy—though for what, Sue isn’t quite sure (in the paper, he hypothesized that it might contribute to an evolutionary need for men to be aggressive in “the high stakes game males play” of selecting a mate.

“The concept of a man flu, as commonly defined, is potentially unjust,” Sue protested in the closing arguments of his paper. “Men may not be exaggerating symptoms but have weaker immune responses… leading to greater morbidity and mortality than seen in women.”

But is the concept of a “man flu” really unjust? To find out, The Daily Beast reached out to Sabra Klein—an associate professor at Johns Hopkins University focusing on how males and females differ in their immune responses to viruses and vaccinations—and asked point blank: Is the “man flu” real?

“No, the ‘man flu’ doesn’t exist,” Klein flatly said. Klein said that what people fundamentally misunderstand about how gender interacts with the flu is the fact that “males and females differ in their susceptibility to the flu at different ages,” she said.

“Whether males suffer a worse outcome or females suffer a worse outcome depends on age,” Klein explained. Males suffer on the extreme ends of the spectrum: Boys under puberty and men on the north side of 65 tend to suffer more with respiratory problems and lingering symptoms.

But women demonstrably suffer more between their twenties into their middle ages. Why that’s the case isn’t completely clear. “Part of that can be that pregnancy increases the severity of influenza,” Klein said. “Among non-pregnant women, there’s a more vigorous immune system response”—often apparent as women exhibit higher rates of a lingering cough after a respiratory infection, for example, which Klein said is medical proof that the lungs were damaged from the immune system’s attack on the virus and the tissue is slowly repairing.

Sue’s defense of the man flu has garnered immense media interest—he told The Daily Beast that he had received about 100 requests for interviews—along with “attack emails calling me a misogynist.” But he pointed out the fact that the Christmas issue of the BMJ is traditionally a lighthearted one, and that “when you tackle a controversial topic, you’ll get criticized for it.”

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Sue, a practicing doctor who believes he’s suffered from “man flu” (though he said he’s “neurotic about hand hygiene” so rarely gets sick), admitted that his literature review doesn’t address the fact that there is a potential bias woven in. For one thing, men are famously terrible at going to the doctor. For another, a lot of what we know about the flu’s effects on the body is through mice studies; while potentially instructive, mice aren’t humans.

“But all stereotypes are based on some truth,” Sue countered when asked if the concept of a “man flu” played on a stereotype and whether he was mistakenly trying to seek an answer to a myth without knowing if it was true or not. “Socially, men tend to suffer from the flu more. In reality, though, I don’t know if my work [in this study] shows that experience.”

Klein said her research indicates that hormones might play a central role in why different genders at different ages fight the flu differently, backing up Sue’s argument that testosterone and estrogen may play a role. But Klein also said that the problem with flu research thus far is that it’s primarily centered on mice. As for the social aspect that Sue reported playing a role, Klein argued that that interpretation of the data is American-focused.

“In some Asian countries, for example, you might have situations where females don’t have equal access to healthcare or treatments, or where baby boys are more valued than baby girls,” Klein said. “It’s not necessarily because of our biology [that we’re susceptible or not to the flu]—it’s a lot to do with societal influences.”

This isn’t the first time the man flu’s existence has been attempted to be proven. A 2010 study from the University of Oxford used mathematical modeling suggested that men are risk takers and think they can get away with not washing their hands or getting a flu shot. A 2016 study argued that women are evolutionarily primed to bear children, which is why they’ve got a stronger flu reaction than men. That’s key, too: While medical evidence is leaning towards suggesting that women are flu warriors, females experience higher rates of autoimmune diseases.

Sue came to his conclusion that the “man flu” existed by reading a lot of medical papers and searching for evidence that supported the theory that men have poorer immune systems compared to women. But as Klein pointed out, the research thus far has been biased in and of itself, often studying mice more than humans; when humans have been studied, it’s been with caveats that make coming to a conclusion nearly impossible, such as limiting drinking or smoking or studying vulnerable parts of the population, like the elderly and children.

What does this mean? The research suggests there’s probably something gendered in how our immune system attacks viruses, but what that something exactly is remains a medical mystery. There are some very real scientific implications that remain unstudied and could lead to a better flu vaccine or treatments like the universal jab—key as the flu continues to evolve and become stronger, less predictable, and more fatal than ever. “If men actually have a different response, we need to know to dose their vaccines and medications differently,” Sue said.

But the existence of the “man flu” is far from medically proven, Klein said. “Saying that it does [exist] assumes all men of all ages suffer worse than women,” she said. “That’s just not true.”

Sue said that he’s been told to “man up” when dealing with the flu, but that might be the wrong advice, he admitted. “I should actually ‘woman up,’” he confessed.