I am not a health professional. I am happy to share here the information that I have researched & my own layperson conclusions; these may save you time in your own research efforts.
I have read that research published December 6, 2022 in The Journal of Allergy and Clinical Immunology gave us a new understanding of perhaps one of the main reasons for more colds & flu in cold weather. We are now told that cell defenses in the nose are weaker when the cells are cold. Leading us to ideas for how to avoid those colds & flu, including that some now hope to see the development of nasal medications that build upon this scientific news. (The study’s info. was reported in the news again this year, leading me to guess that it has not been questioned/disputed over the past year).
It had been thought for years that cold & flu viruses take hold more often during colder temperatures because many people head indoors then. And that being indoors in groups then leads to viruses transferring more easily from person to person.
After virus particles make their way in to our noses, generally our cells there activate quickly to start expelling them. But findings of the new study indicate that colder temperatures significantly disrupt that immune response in our noses. The 2022 study indicates that “reducing the temperature inside the nose by as little as 9 degrees Fahrenheit (5 degrees Celsius) kills nearly 50% of the billions of helpful virus & bacteria-fighting cells in the nostrils”.
Therefore we have learned how being cold may lead to catching a cold. Because cold air weakens the body’s immune response — especially in the nose which is a first site of contact for respiratory viruses, is an important part of the body’s immune response.
One opinion I saw expressed that: “this study is the first to offer a biological explanation for why people are more likely to develop upper respiratory infections like cold, flu, and COVID-19 in colder temperatures”.
One of my conclusions, a partial protective remedy for now: wearing some nose covering (a clean scarf, a covid face mask) in cold outside weather. To warm the air going into the nose. Result: less colds/flu? I am trying the idea out myself this Winter, because: I am always ready for something to help make a happier Winter experience.