We’ve all heard our mom’s and grandmom’s advice, “don’t go out without your coat; you’ll catch a cold.” Once dismissed as an “old wives’ tale,” researchers have ended the debate once and for all!
Turns out our mothers were right!
With much of the country now in the grip of unprecedented cold temperatures, scientists at the Mass Eye and Ear and Northeastern University have found a biological reason why cold weather does indeed lead to an increased likelihood of getting a cold or flu infection. It turns out, your nose, your body’s first line of defense against invading pathogens, does not work as well in cold temperatures.
“Conventionally, it was thought that cold and flu season occurred in cooler months because people are stuck indoors more where airborne viruses could spread more easily,” said Benjamin S. Bleier, MD, FACS, director of Otolaryngology Translational Research at Mass Eye and Ear and senior author of the study. “Our study, however, points to a biological root cause for the seasonal variation in upper respiratory viral infections we see each year….”
The nose is one of the first points of contact between the outside environment and inside the body and, as such, a likely entry point for disease-causing pathogens. Pathogens are inhaled or directly deposited — such as by the hands — into the front of the nose, where they work their way backward through the airway and into the body, infecting cells, which can lead to an upper respiratory infection.
The nose does a pretty good job of defending against that with cells in the front of the nose that detect bacteria and then release billions of tiny fluid-filled sacs called extracellular vesicles, or EVs, into the mucus to surround and attack the bacteria. Dr. Bleier compares the release of this EV swarm to “kicking a hornets’ nest.”
Dr. Bleier’s and his team’s most recent research has discovered that the release of the EVs is slowed or inhibited in colder weather.
“[Our] findings provide a mechanistic explanation for the seasonal variation in upper respiratory infections,” said Di Huang, Ph.D., the lead author on the study.
The study not only provides an explanation as to why colds and flu infections happen more often in the winter months, but could provide an avenue for more effective therapeutics.
The researchers say they can imagine ways in which their findings could be used to develop therapeutics that can induce and strengthen the nose’s innate immune response. For example, “a drug therapy, such as a nasal spray, could be designed to increase the number of EVs in the nose,” said Dr. Huang