Why Catching Flu Might Protect You From The Common Cold
It is said that what doesn't kill you makes you stronger, and for Britons unfortunate enough to get flu this winter, there may be some comfort in learning that it could protect them against catching a cold.
New research from the University of Glasgow has found that people who suffered from influenza over a nine year period were 70 per cent less likely to have acquired rhinoviruses, or the common cold.
The research was based on data from 12,654 patients who tested positive for respiratory viruses between 2005 and 2013 at NHS Greater Glasgow and Clyde board.
Around 1,000 of those patients had acquired more than one virus, and experts were keen to see how the different infections might interact.
The most striking interaction was found between influenza and the common cold. Dr Sema Nickbakhsh, from the Centre for Virus Research at the University of Glasgow, who was first author on the paper, said: “One really striking pattern in our data is the decline in cases of the respiratory virus rhinovirus, which is typically a mild common cold causing virus, occurring during winter, around the time that 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.
“There are various possibilities we’re investigating, such as these viruses are competing for cells to infect in the body, or the immune response to one virus makes it harder for another unrelated virus to infect the same person.”
It has previously been observed before that common cold infections appear to be less frequent in the influenza season and vice versa. But the new study is the first with enough samples to provide strong evidence for this interaction at both the population and individual level.
Researchers say that understanding how these distinct viruses inhibit each other could help public health planning to improve forecasting of respiratory disease outbreaks and strategies for controlling disease spread.
While viruses of the same species, such as different strains of influenza, might be expected to compete with each other, it is the first study to show that different types of virus also interact.
However the researchers point out that the results could be driven by people with flu simply staying indoors, so they consequently do not catch cold. The protective window is thought to last several weeks.
Dr Pablo Murcia, also of Glasgow University who led the research, added: “Traditionally people have studied viruses in isolation – you study only flu or rhinovirus – but we’ve shown here that we need to also be studying these viruses together like it’s an ecosystem.
“Studying interactions between viruses could help to explain why different viruses circulate in different seasons or why they affect different age groups, and within the body why certain types of viruses infect different parts of the respiratory tract, like the nose or the lungs.
“My team are now doing experiments to try and understand how respiratory viruses, including influenza and rhinovirus, interact.
“If we understand how viruses interact and how certain viral infections may favour or inhibit each other, then maybe we can develop better ways to target viruses.”
The research was published in the Proceedings of the National Academy of Sciences.