Man flu could be real after all, scientists say

Viruses may ‘go easy’ on women so they can be passed on to children, according to researchers from Royal Holloway, University of London

Pope Francis blows his nose during a 2013 ceremony in Rome (Getty Images)

Some infectious diseases have evolved to be more harmful to men than women, a new study has found – suggesting those who scoff at so-called ‘man flu’ may have to think twice.

Certain viruses may ‘go easy’ on women in an attempt to be passed on to children through pregnancy, birth or breast-feeding, according to researchers at Royal Holloway, University of London.

This means men could be harder hit by the infection and can suffer more severe symptoms of any resulting illness.

“Viruses may be evolving to be less dangerous to women, looking to preserve the female population,” said researcher Francesco Ubeda.

“The virus wants to be passed from mother to child, either through breastfeeding, or just through giving birth.“

Men are more likely than women to die if they are infected with a number of diseases including chickenpox and tuberculosis, which is one and a half times more fatal for men, according to the New Scientist.

While this difference in mortality rates between the sexes is often put down to a stronger immune system in women, the study suggests mutations in the virus itself may actually be to blame.

Dr Ubeda’s co-author Vincent Jansen said a virus might be able to tell if its host were a man or a woman by detecting hormonal and other differences, although it was not yet clear how exactly it would do this.

He told the New Scientist it could therefore be possible to manipulate a virus by tricking it to “think it’s in a female body rather than a male body and therefore take a different course of action”.

The researchers used a mathematical model to study the role that gender played in the behaviour of viruses.

Their findings showed it was theoretically possible that viruses could be evolving to be less dangerous to women, Dr Ubeda told the BBC.

“We're turning it on its head and taking the pathogen's eye view,” he said.

“We show theoretically it is possible, which is challenging, but we haven't proven what the mechanism is that would trigger this difference, or that there will be a difference in the pathogen's behaviour between in men and women.”

An independent expert in the field told the broadcaster the results were “intriguing”.