You’re more likely to get flu from a fat person

Next time you are about to squeeze into a seat on public transport next to a very overweight passenger, think again.

A study published in the Journal for Infectious Diseases suggests you might be more likely to catch flu from an obese person than from a regular sized member of the population because their bodies tend to harbour the virus for longer.

Consequently, they risk spreading the bug to others for up to twice as long as those of a normal weight, it is thought.

Evidence already shows that those classed as obese - individuals with a body mass index of 30 or more - have a greater risk of suffering complications like pneumonia and death.

But no one had previously measured whether they may be infectious for longer. The US study of 1800 people over three flu seasons, led by the University of Michigan, found that obese adults with flu symptoms were infectious with the influenza A virus for 42%longer than those of normal weight.

Those who were only mildly ill, or who had no symptoms, were contagious for more than twice as long.

Obesity alters the body’s immune response and causes chronic inflammation, which may allow a virus such as flu to hang around for longer.

Dr Aubree Gordon, from the University of Michigan School of Public Health, said: “This is the first real evidence that obesity might impact more than just disease severity. It might directly impact transmission as well.”

Infected obese adults with one or fewer symptoms were capable of passing on the virus for 104% longer than non-obese adults.