UK scientists say some viruses have evolved to cause less severe diseases in women than in men – possibly providing evidence that “man flu” actually does exist.
They hypothesise that women can help viruses spread in ways men can’t – through pregnancy, birth and breastfeeding – so it makes evolutionary sense for the pathogen to keep women healthier.
It had been thought women recovered quicker from a heavy cold due to a stronger immune response.
But Dr Francisco Ubeda of Royal Holloway University , South West London, said viruses may adapt to preserve women as they are “a more valuable host”.
He added: “The virus wants to be passed from mother to child. Survival of the fittest is relevant to all organisms, not just animals and humans.”
It may also explain why a virus that causes adult T-cell leukaemia is less often found in women, Dr Ubeda said.
Dr Ubeda went on: “Pathogens are adapting to be less virulent in women to increase their chances of being passed on to the next generation during pregnancy, birth and infancy.
“Survival of the fittest is relevant to all organisms, not just animals and humans. It is entirely probable this sex-specific virulent behaviour is happening to many other pathogens causing diseases. It is an excellent example of what evolutionary analysis can do for medicine.”
Previous research has shown men suffer more from a high temperatures than women when they have flu, despite being accused of exaggerating symptoms to gain sympathy.