Why does the cold make us sick?

We already knew that with mingling indoors, in the winter, Facilitate the spread of some germs. It is also known that some viruses thrive perfectly in cold and damp. But with a new study, we are It is better understood how low temperatures can weaken the immune defenses in the nose.

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Scientists from a clinic in Boston, attached to Harvard, have already done so Tissue samples from the nose are exposed to the laboratory (article in English) to three different viruses: two rhinoviruses and a coronavirus — which is not SARS-Cov-2 — and they noticed what was happening.

At room temperature, the nasal defense system works: any penetration of bacteria or virus causes nasal cells to secrete billions of tiny globules, which are extracellular sacs. They contain antibacterial proteins or are able, thanks to their receptors, to catch and block the virus before it enters the cells of the nose.

But if the temperature drops to 4 degrees Celsius or 5 degrees°againstFor a quarter of an hour, which can happen when you breathe very cold air outside, the researchers found in the laboratory that the nasal mucous membranes lose their strength slightly. The production of these extracellular vesicles decreases by 42%. Thus the defense phalanx at nose level is much less operational.

The mask remains the best defense

Is it then possible to recreate this nasal defense mechanism that weakens with a cold, through medication? The question arises, one can imagine for example a spray, which can re-enhance the antiviral defenses of the nose. But before considering treatments, scientists will have to retest with other viruses and at other temperatures.

In the meantime, there is a ready solution to avoid getting sick, even by 5 degrees Celsius outside. : mask. It remains the most effective, because with it, viruses can no longer invite themselves into our noses.