Got the flu? At least it keeps a cold away

Experts find surprising link between common viruses

THERE is good news for those concerned that catching a cold could ruin the festive season.

People are much less likely to end up sneezing and spluttering at this time of year, with scientists suspecting the flu protects people against colds.

A study has shed light on the dramatic annual reduction in the number of common colds between October and May.

Scientists have found people infected with flu, three-quarters of whom will exhibit symptoms, may be protected against rhinovirus, which is the most common cause of colds.

Looking at 36,000 people with respiratory viruses over nine years, researchers found only 8 per cent were infected with two viruses at the same time. Patients who had the flu were 70 per cent less likely to get a cold, compared to those with other respiratory viruses, the figures suggest.

While it is vital for vulnerable people such as children, over-65s and pregnant women to get vaccinated to protect against dangerous complications, some healthy adults take their chances.

However there may now be an upside, as expert believe the flu colonises cells in the throat so the cold virus cannot attack them.

Dr Sema Nickbakhsh, lead author of the study from the University of Glasgow’s Centre for Virus Research, said: ‘It is a striking result from our study that rhinovirus, which typically causes the common cold, declines in the winter as flu activity increases.

‘In the same way as lions and spotted hyenas compete for food resources in the Masai Mara, we believe respiratory viruses may be competing for resources in the respiratory tract. Or it may be that the immune response to the flu then also fights off colds.’

The study, published in the journal Proceedings of the

National Academy of Sciences, is the first to study patients who had been tested for 11 respiratory viruses at the same time over an extended period.

The research involved patients living within the Greater Glasgow and Clyde health board area. Experts, who created computer models for 11 virus infections over nine years, found only influenza A, a strain which includes swine flu, and rhinovirus were rarely found together.

The researchers believe that the flu may destroy cells in the respiratory tract, as well as the ‘doorway’ on the outside which lets other viruses in.

But a short-lived immune reaction elicited by the flu, where the body produces a chemical called interferon to fight it for the first few days, may also provide protection against colds.

Dr Pablo Murcia, senior author of the research from the University of Glasgow, said: ‘If we understand how certain viral infections may favour or inhibit each other, then maybe we can develop better ways to target viruses.’

‘Competing for resources’