For years, the thought was that cold and flu season happened during the winter months because we’re spending more time inside together in poorly ventilated spaces. However, new research out of Yale University suggests that the frigid winter temperatures may actually be to blame.
One in five people carry the rhinovirus – the most frequent cause of the common cold – in their nasal passages at any one time. Usually our immune system is strong enough to stop the virus in its tracks. But, scientists found that when the core body temperature inside the nose falls by five degrees, the immune system struggles to fight back against the intruder.
So, your mother was right when she told you to bundle up when you go outside. Wearing a scarf over your nose may not stop the virus from entering your body, but it could increase your immune system’s ability to put up a good fight. “We found that the innate immune response to the rhinovirus is impaired at the lower body temperature compared to the core body temperature,” said Professor Akiko Iwasaki, an immunobiology expert at Yale University. “That proves it’s not just virus intrinsic, but it’s the host’s response that’s the major contributor. In general, the lower the temperature, it seems the lower the innate immune response to viruses. In other words, the research may give credence to the old wives’ tale that people should keep warm, and even cover their noses, to avoid catching colds.”
In the past, researchers were convinced that the rhinovirus replicates more readily in the slightly cooler environment of the nasal cavity than in the warmer lungs. However, those studies focused on how body temperature influenced the virus itself as opposed to the immune system.
The current study strongly suggested that varying temperatures influenced the immune response rather than the virus itself. Scientists found that with immune deficiencies, the virus was able to replicate more efficiently at a lower temperature. Yale researchers hope that the findings could also help explain how temperature affects immune response to other conditions, such as childhood asthma. Although the common cold is usually nothing more than some congestion and a runny nose for many people, it can cause severe breathing problems for children with asthma. The study was published in the Proceedings of the National Academy of Sciences.