New research appears to give credence to the old wives’ tale that people should keep warm, and even cover their noses, to avoid catching a cold.
The study, published in the Proceedings of the National Academy of Sciences, shows that the common cold virus thrives and reproduces better in the cooler temperatures inside the nose, rather than at core body temperature.
Temperature and immunity
Previous studies have shown that the most frequent cause of the common cold, the rhinovirus, replicates more readily in the slightly cooler environment of the nasal cavity than in the warmer lungs. But, the focus of those studies has been on how body temperature influences the virus as opposed to the immune system.
To investigate the relationship between temperature and immune response, researchers examined the cells taken from the airways of mice. They compared the immune response to rhinovirus when cells were incubated at 37 degrees Celsius, or core body temperature, and at the cooler 33 degrees Celsius.
“We found that the innate immune response to the rhinovirus is impaired at the lower body temperature compared to the core body temperature,” Akiko Iwasaki, professor of immunobiology at Yale University.
The findings also strongly suggest that varying temperatures influence the immune response, rather than the virus itself.
Kids with asthma
Researchers observed viral replication in airway cells from mice with genetic deficiencies in the immune system sensors that detect virus and in the antiviral response. They found that with these immune deficiencies, the virus was able to replicate at the higher temperature.
“That proves it’s not just virus intrinsic, but it’s the host’s response, that’s the major contributor,” Iwasaki says.
Although the research was conducted on mouse cells, it offers clues that may benefit people, including the roughly 20 percent of us who harbor rhinovirus in our noses at any given time.
“In general, the lower the temperature, it seems the lower the innate immune response to viruses,” Iwasaki says.
The researchers hope to apply their findings to how temperature affects immune response to other conditions, such as childhood asthma.
While the common cold is no more than a nuisance for many people, it can cause severe breathing problems for children with asthma, says Ellen Foxman, a postdoctoral fellow in Iwasaki’s lab.
Future research may investigate the immune response to rhinovirus-induced asthma.
The National Institutes of Health and the National Science Foundation provided funding for the study.
Source: Yale University