What's the difference between 'man flu' and flu?

Man flu could refer to a number of respiratory infections – a cold, flu, even a mild case of COVID. So it’s difficult to compare man flu with flu.

But for simplicity, let’s say man flu is actually a cold. If that’s the case, man flu and flu have some similar features.

Both are caused by viruses (but different ones). Both are improved with rest, fluids, and if needed painkillers, throat lozenges or decongestants to manage symptoms(external link).

Both can share(external link) similar symptoms. Typically, more severe symptoms such as fever, body aches, violent shivering and headaches are more common in flu (but sometimes occur in colds). Meanwhile sore throats, runny noses, congestion and sneezing are more common in colds. A cough is common in both.

Flu is a more serious and sometimes fatal respiratory infection caused by the influenza virus. Colds are caused by various viruses such as rhinoviruses(external link), adenoviruses(external link), and common cold coronaviruses, and are rarely serious. Colds tend to start gradually(external link) while flu tends to start abruptly.

Flu can be detected(external link) with laboratory or at-home tests. Man flu is not an official diagnosis.

Severe flu symptoms may be prevented with a vaccine, while cold symptoms can't.

Serious flu infections may also be prevented or treated(external link) with antiviral drugs such as Tamiflu. There are no antivirals for colds.

Again, let’s assume man flu is a cold. Do men really have worse colds than women? The picture is complicated.

One study(external link), with the title “Man flu is not a thing”, did in fact show there were differences in men’s and women’s symptoms.

Image credit: Canva

This study looked at symptoms of acute rhinosinusitis. That’s inflammation of the nasal passages and sinuses, which would explain a runny or stuffy nose, a sinus headache or face pain.

When researchers assessed participants at the start of the study, men and women had similar symptoms. But by days 5 and 8 of the study, women had fewer or less-severe symptoms. In other words, women had recovered faster.

But when participants rated their own symptoms, we saw a somewhat different picture. Women rated their symptoms worse than how the researchers rated them at the start, but said they recovered more quickly.

All this suggests men were not exaggerating their symptoms and did indeed recover more slowly. It also suggests women feel their symptoms more strongly at the start.

It’s not straightforward to tease out what’s going on biologically.

There are differences(external link) in immune responses between men and women that provide a plausible reason for worse symptoms in men.

For instance, women generally produce antibodies more efficiently, so they respond more effectively to vaccination. Other aspects of women’s immune system also appear to work more strongly(external link).

So why do women tend to have stronger immune responses(external link) overall? That’s probably partly because women have two X chromosomes while men have one. X chromosomes carry important immune function genes(external link). This gives women the benefit of immune-related genes from two different chromosomes.

Oestrogen (the female sex hormone) also seems to strengthen the immune response, and as levels vary throughout the lifespan, so does(external link) the strength of women’s immune systems.

Men are certainly more likely to die from some infectious diseases, such as COVID. But the picture is less clear with other infections such as the flu, where the incidence and mortality between men and women varies widely(external link) between countries and particular flu subtypes and outbreaks.

Infection rates and outcomes in men and women can also depend on the way a virus is transmitted(external link), the person’s age, and social and behavioural factors.

For instance, women seem to be more likely to practice protective behaviours(external link) such as washing their hands, wearing masks or avoiding crowded indoor spaces. Women are also more likely(external link) to seek medical care when ill.

Some evidence suggests men are not over-reporting symptoms, and may take longer to clear an infection. So they may experience man flu more harshly than women with a cold.

So cut the men in your life some slack. If they're sick, gender stereotyping is unhelpful, and may discourage men from seeking medical advice.