Why men might have a point about ‘man flu’ – viruses want to kill men more than women, scientists find


A man lies ill on a sofa
Men are right, viruses really do affect them more than women 

Historically men have been mocked for their inability to handle even mild viruses, with the term ‘man flu’ often used to describe the male experience of the common cold.

But a new study suggests men might have a point. Some viruses really are out to get them.

Researchers at Royal Holloway University have discovered that certain viral infections have evolved to be more virulent in men.

They appear to be particularly nasty if they are the sort of virus that is transmitted from mother to child, such as rubella, chickenpox, zika and hepatitis.

Put simply, women are more valuable to the virus than men are because they can pass it on to more people.

“Viruses may be evolving to be less dangerous to women, looking to preserve the female population,” said Dr Francisco Úbeda, of the School of Biological Sciences at Royal Holloway.

“The reason why these illnesses are less virulent in women is that the virus wants to be passed from mother to child, either through breastfeeding, or just through giving birth.”

A woman blows her nose
Viruses are keen to keep women alive because they are more likely to pass them on to their children 

Researchers looked at the virus Human T-cell Lymphotropic Virus Type 1 (HTLV-1), which can cause leukaemia in infected individuals.

Infected women tend to develop leukaemia less often than men when there is more mother-to-child transmission.

Death due to infectious diseases is often higher in men than in women, but it has previously been attributed to differences in the immune system of each sex.

The study suggests it is the virus itself which prevents women becoming too ill.

“It has already been established that men and women react to illness differently, but evidence shows that viruses themselves have evolved to affect the sexes differently,” said Professor Vincent Jansen, from the School of Biological Sciences at Royal Holloway, University of London.

The researchers used mathematical modelling to show that natural selection favours viruses that have a lower rate of fatality in women than in men, if the virus can be passed from person to person and from mother to child, either in childbirth, breast-feeding, or close contact in infancy.

The HIV virus under a microscope 
HIV is another virus which appears to more virulent in men more than women  

They also looking at how HTLV-1 affects people in Japan and the Caribbean. The research showed that HTLV-1 is about 2 to 3.5 times more likely to progress to become Adult T-cell Leukaemia (ATL), which is lethal, in Japanese men than women.

In the Caribbean, however, the likelihood of HTLV-1 progressing to leukaemia is roughly equal in men and women.

The researchers believe that because breastfeeding is more prolonged in Japan, giving more opportunity for it to be passed onto offspring, the HTLV-1 virus has evolved to become less fatal to women than in the Caribbean where breastfeeding is shorter.

Women are more valuable as hosts for the pathogens when they are able to pass on the pathogen in more ways than men, who are only capable of transmission from person to person.

“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,” added Dr Úbeda.

 “Survival of the fittest is relevant to all organisms, not just animals and humans.

It’s entirely probable that this sex-specific virulent behaviour is happening to many other pathogens causing diseases. It’s an excellent example of what evolutionary analysis can do for medicine.”

Source: Nature Communications.

The ‘man flu’ is real – viruses want to kill men more than women.


Throughout history, men have been ridiculed for their apparent inability to handle simple viruses like the common cold – otherwise referred to as the “man flu” in these cases.

But as it turns out, there may be some truth to the man flu label as researchers find that certain viruses may present themselves more virulently in men than in women.

And it may have to do with evolution.

Researchers believe viruses favour women as hosts because they are more likely to pass on the virus to their babies.

“It has already been established that men and women react to illness differently, but evidence shows that viruses themselves have evolved to affect the sexes differently,” Vincent Jansen, professor at the School of Biological Sciences at Royal Holloway University of London, and co-author of the study, said in a statement.

Researchers looked at HTLV-1, a virus known to cause leukemia in infected people.

Infected women tend to develop leukemia less often than men, who are more likely to die from the disease.

By using mathematical modelling, researchers set out to show that natural selection favours viruses that have a lower rate of death in women than in men, especially if the virus can be passed from person to person and from mother to child.

Researchers used population samples from Japan and the Caribbean.

They found that Japanese men infected with the HTLV-1 virus were two to 3.5 times more likely to develop leukemia than women. However, the likelihood of the virus progressing to leukemia was about equal in men and women in the Caribbean.

Scientists believe the virus has become less fatal in women because the HTLV-1 virus can be passed through breastfeeding, a practice that is more prolonged in Japan.

Researchers concluded that women were proven to be more valuable hosts for pathogens because they are able to pass them on in more ways than men can.

“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,” says Dr. Francisco Ubeda of Royal Holloway. “Survival of the fittest is relevant to all organisms, not just animals and humans. It’s entirely probable that this sex-specific virulent behaviour is happening to many other pathogens causing diseases.”

A previous study by Standford University School of Medicine in 2013 found that men and women also have different reactions to flu vaccinations.

Standford researchers found women had a stronger antibody response than men, which gave women better protection against the flu.

This, they say, was more apparent in men with higher testosterone levels which scientists believe weakens a man’s immune system.

Man flu isn’t a myth after all .


Men get sick because they don’t have the hormones that boost women’s immune system, according to new research

The study by Stanford University School of Medicine, examined the reactions of men and women to vaccination against flu

The study by Stanford University School of Medicine, examined the reactions of men and women to vaccination against flu Photo: Alamy

Scientists from Harvard University have shown that a lack of oestrogen makes men more likely to succumb to pneumonia and other respiratory diseases.

Yet a simple dose of oestrogen was enough to cure both males and females of the serious lung infection.

Professor Lester Kobzik at the Harvard University School of Public Health found females are naturally more resistant to respiratory infections than males.

The study showed that increased resistance to bacterial pneumonia in female mice is linked to the enzyme nitric oxide synthase 3 (NOS3), which is ultimately activated by the release of the female sex hormone estrogen

Female mice and male mice that had been treated with oestrogen were able to clear the bacteria from their lungs more rapidly than normal male mice.

The scientists then took another set of male and female mice and removed the gene responsible for the production of NOS3, an enzyme activated by oestrogen.

They found that deleting this gene meant that the female mice were no longer more resistant to infection.

The team hopes that, in the future, this knowledge could be used to enhance resistance to common and serious lung infections and prevent flu developing into more serious pneumonia.

Professor Kobzik said: “Ultimately, this work could be especially useful in reducing risk of secondary bacterial pneumonias during seasonal or pandemic influenza.

“We were quite pleased that the work led us to NOS3-targeting drugs that are already available and that can indeed improve resistance to pneumonia in our mouse model.”

Are men unfairly castigated for having “man flu” and running to their sick beds at the merest sign of a sniffle?


Man sneezing on a busHe will be in bed soon with a damp towel on his brow…

Research suggests that women are at greater risk of getting flu than men because they tend to spend more time around children, who are more likely to have a flu-like illness in the first place.

A nationwide flu survey carried out by London School of Hygiene and Tropical Medicine during last winter found that women were 16% more likely to say they had flu symptoms.

So is it really women who are making all the fuss about being unwell?

This winter, the online flu survey is up and running again and aiming to find out the answer.

 

The survey needs people of all ages around the country to report any flu-like symptoms by filling in an online questionnaire.

This data will be used to map the spread of flu across the country during the winter.

Researchers can then analyse how the virus spreads and who it affects.

How ill?

Dr Alma Adler, who runs the project, says they wanted to find out more about gender differences and flu in this year’s survey.

“We haven’t found any evidence of ‘man flu’ yet.

“The biggest risk factor is having children under the age of 18 and for this reason women are more at risk of flu.

“This year we have included some new questions, such as ‘How bad do you feel?’

“People can answer on a number scale of one to 10.”

What is flu?

How an influenza virus particle might look
  • Flu is a respiratory illness linked to infection by the influenza virus.
  • Symptoms usually include headache, fever, cough, sore throat, aching muscles and joints.
  • Influenza occurs most often in winter and usually peaks between December and March.
  • The virus was first identified in 1933.
  • There are two main types that cause infection: influenza A and influenza B
  • New strains of the virus are constantly emerging, which is why the flu vaccine should be given each year.

This is the crucial part, asking people how they feel when they have flu, by delving into the psychology of illness – not just the science.

‘More sensitive’

And that could help scientists discover if men and women experience flu differently.

John Oxford, professor of virology at Queen Mary, University of London, says there is no scientific evidence for “man flu” but there is a difference in behaviour.

“We know that women react differently to infection. They are more sensitive to their health. Men bluster around a bit.

“So there are differences in how men and women perceive illness and then differences in behaviour.

“Men think they are going to die when they are unwell, so they go to bed and expect women to look after them.”

Dr Douglas Fleming, from the Royal College of GPs’ flu research unit, says there is no rule when it comes to how flu viruses affect people.

“Every flu virus is different. It depends on the strain. We don’t know ahead of time how it will affect people.

“Different viruses affect men, women and children differently.”

Weaker sex

Previous research from the University of Cambridge came to a different conclusion.

It found evidence that women were better at fighting infections than men.

Man getting the seasonal flu jabThe over-65s are among those entitled to a free flu jab

Evolutionary factors and hormonal differences were thought to make males more susceptible to infection than females.

In the animal world too, across a range of species, males tend to be the “weaker sex” in terms of immune defences, the Cambridge research team said.

This would back up the argument that “man flu” exists because men would be more susceptible to viruses and therefore more likely to be unwell.

But if children are the main sufferers and harbourers of influenza, spreading it to their parents and grandparents, then won’t mothers automatically be in the firing line?

Prof Oxford says men will still be infected just as much.

“If the parents are sleeping together in the same bed, spending at least eight hours in the same room sharing pillows, then the flu virus will soon move on to the husband.”

Unpredictable

The Health Protection Agency (HPA) started its weekly monitoring of flu activity in the UK population in October.

So far this winter, the number of people with flu symptoms going to see their GP is low (6.9 per 100,000 in England).

This could explain why just 65% of those aged over 65 and 32% of pregnant women have taken up the offer of a flu vaccine.

Dr Richard Pebody, head of seasonal flu surveillance at the HPA, said they are hoping this winter will mirror last winter’s trend.

“The 2011/2012 flu season was one of the lowest on record – following two years of high flu activity, including the 2009 flu pandemic. This demonstrates how unpredictable the flu season can be.”

Whether you are a man or a woman, there is a chance you could be infected by the flu virus in the coming months.

If you are in any of the “at risk” groups, the key is to be protected in advance by getting the flu jab.

Then keep a box of tissues and a hot water bottle handy.

Man flu is no myth say scientists, with ‘manly’ men more susceptible


Men with high levels of testosterone have a secret flaw – less effective immune systems, researchers have discovered

Man flu may not be a myth after all, as scientist have found that men with high levels of testosterone have a hidden flaw – weak immune systems.

The discovery could explain why men are more susceptible than women to a whole range of bacterial, viral, fungal and parasitic infections, researchers said.

It may also be the reason why men’s immune systems respond less strongly to vaccinations against influenza, yellow fever, measles and hepatitis, along with many other infectious diseases.

Those who take testosterone supplements in the quest to gain muscle meanwhile, could be making themselves more susceptible to illness.

“This is the first study to show an explicit correlation between testosterone levels, gene expression and immune responsiveness in humans,” said US lead scientist Professor Mark Davis, from Stanford University.

“It could be food for thought to all the testosterone-supplement takers out there.”

The researchers studied how the immune systems of 34 men and 53 women were stimulated by the flu vaccine.

The jab generated a bigger boost in protective antibodies in women, with further analysis revealing activity that, in high testosterone men, was associated with a weakened antibody response. Men with low testosterone were not affected the same way.

Testosterone’s anti-inflammatory properties may explain why it can weaken the immune system, said scientists writing in the journal Proceedings of the National Academy of Sciences.

Prof Davies said the reason why testosterone weakens the immune system yet boosts muscle power and aggression, may be linked to the man’s evolutionary role.

Men are more likely than women to suffer injuries from competitive encounters, as well as their traditional roles of hunting, defence and potentially dangerous physical work, Prof Davies said. The dampening down the immune system makes male less susceptible to a potentially fatal over-reaction to infections, especially those from wounds.

“Ask yourself which sex is more likely to clash violently with, and do grievous bodily harm to, others of their own sex,” Prof Davis added.

Man flu is no myth say scientists, with ‘manly’ men more susceptible


Man flu may not be a myth after all, as scientist have found that men with high levels of testosterone have a hidden flaw – weak immune systems.

The discovery could explain why men are more susceptible than women to a whole range of bacterial, viral, fungal and parasitic infections, researchers said.

It may also be the reason why men’s immune systems respond less strongly to vaccinations against influenza, yellow fever, measles and hepatitis, along with many other infectious diseases.

Those who take testosterone supplements in the quest to gain muscle meanwhile, could be making themselves more susceptible to illness.

“This is the first study to show an explicit correlation between testosterone levels, gene expression and immune responsiveness in humans,” said US lead scientist Professor Mark Davis, from Stanford University.

“It could be food for thought to all the testosterone-supplement takers out there.”

The researchers studied how the immune systems of 34 men and 53 women were stimulated by the flu vaccine.

The jab generated a bigger boost in protective antibodies in women, with further analysis revealing activity that, in high testosterone men, was associated with a weakened antibody response. Men with low testosterone were not affected the same way.

Testosterone’s anti-inflammatory properties may explain why it can weaken the immune system, said scientists writing in the journal Proceedings of the National Academy of Sciences.

Prof Davies said the reason why testosterone weakens the immune system yet boosts muscle power and aggression, may be linked to the man’s evolutionary role.

Men are more likely than women to suffer injuries from competitive encounters, as well as their traditional roles of hunting, defence and potentially dangerous physical work, Prof Davies said. The dampening down the immune system makes male less susceptible to a potentially fatal over-reaction to infections, especially those from wounds.

“Ask yourself which sex is more likely to clash violently with, and do grievous bodily harm to, others of their own sex,” Prof Davis added.