Yale study finds cold virus thrives in cooler areas of body

A new Yale University study released Monday suggests the common cold virus can reproduce itself more efficiently in cooler temperatures found inside the nose than in the body's warmer core areas.

These findings, recently published in Proceedings of the National Academy of Sciences, seem to confirm the popular belief that it’s easier to catch a cold in cool-weather conditions.

Researchers have known that the rhinovirus, the most frequent cause of the common cold, replicates easily in the slightly cooler environment of the nasal cavity than in the warmer lungs, but the focus of previous studies has been on how body temperature influenced the virus instead of the immune system.

To investigate the relationship between temperature and immune response, Yale immunology Professor Akiko Iwasaki and a team of Yale researchers spearheaded by Ellen Foxman, a postdoctoral fellow in Iwasaki's lab, examined cells taken from the airways of mice. The team then compared the immune response to the rhinovirus when cells were incubated at 37 degrees Celsius (core body temperature) and four degrees cooler.

"We found that the innate immune response to the rhinovirus is impaired at the lower body temperature compared to the core body temperature," Iwasaki said.

The study also suggested that the varying temperatures influenced the immune response rather than the virus itself; due to 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 said.

Future research may look at the immune response to rhinovirus-induced asthma.