It is common knowledge that respiratory viral infections – such as common colds, influenza, RSV, and now COVID-19 – are more common in the cold, winter months. The traditional thinking is that this is due to the fact that people congregate more indoors during these cold months, and this allows these viruses to circulate more easily. No doubt this is true. At the same time, there may be something else that causes these viruses to infect us more during the winter.

When I was a teenager, I became horribly sick after sleeping in front of a fan for hours on end (it was summertime and very hot). I also remember reading – way back in medical school – that respiratory viruses are able to attach better to the nasal mucosa in cold air. New research has elucidated the possible mechanism behind this. It turns out that our nasal mucosa has inherent, innate anti-viral properties.

There are things called “nasal epithelium-derived extracellular vesicles in innate Toll-like receptors” that line our nasal epithelium, or the lining of our noses. According to this research, these extracellular vesicles induce “a swarm-like increase in the secretion of nasal epithelial EVs via the TLR3 signaling,” and this helps prevent viral infections from happening.

Cold air, it turns out, seems to disrupt this process:

And so this may help explain why colds are more common in the winter months.

Now, it is true that there is also increased influenza in the winter months, even in warmer climates such as the Southern part of the U.S. And COVID did not stop during the summer, although it was definitely less prevalent than in the winter. Still, this may help explain part of the reason why respiratory viral infections are more common during the cold winter months.

Therefore…there seems to be a scientific case for a scarf: the scarf can help keep the upper airway nice and warm, so this innate antiviral defense system can stay as intact as possible. The same is true with a…dare I say it…mask (or balaclava) in the cold as well. It should be able to do the same thing: keep the ambient air in the upper airway warm.

Is this fool-proof? Of course not. But it is one possible extra arrow in the quiver to fight against respiratory viral infections in the winter. It is relatively inexpensive, does not involve drugs or medicines, and can be fashionable as well! And, with how annoying – and potentially deadly – some of these respiratory viruses can be, we need all the defenses we can muster.