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A chill is in the air, and you all know what that means — it’s time for cold and flu season, when it seems everyone you know is suddenly sneezing, sniffling or worse. It’s almost as if those pesky cold and flu germs whirl in with the first blast of winter weather.
Yet germs are present year-round — just think back to your last summer cold. So why do people get more colds, flu and now Covid-19 when it’s chilly outside?
In what researchers are calling a scientific breakthrough, scientists behind a new study may have found the biological reason we get more respiratory illnesses in winter. It turns out the cold air itself damages the immune response occurring in the nose.
“This is the first time that we have a biologic, molecular explanation regarding one factor of our innate immune response that appears to be limited by colder temperatures,” said rhinologist Dr. Zara Patel, a professor of otolaryngology and head and neck surgery at Stanford University School of Medicine in California. She was not involved in the new study.
In fact, reducing the temperature inside the nose by as little as 9 degrees Fahrenheit (5 degrees Celsius) kills nearly 50% of the billions of virus and bacteria-fighting cells in the nostrils, according to the study published Tuesday in The Journal of Allergy and Clinical Immunology.
“Cold air is associated with increased viral infection because you’ve essentially lost half of your immunity just by that small drop in temperature,” said rhinologist Dr. Benjamin Bleier, director of otolaryngology translational research at Massachusetts Eye and Ear and an associate professor at Harvard Medical School in Boston.
“it’s important to remember that these are in vitro studies, meaning that although it is using human tissue in the lab to study this immune response, it is not a study being carried out inside someone’s actual nose,” Patel said in an email. “Often the findings of in vitro studies are confirmed in vivo, but not always.”