Warm noses are better at fighting infections, research published in the peer-reviewed Journal of Allergy and Clinical Immunology has shown.
Experts indicated that for a long time, cold weather was associated with respiratory infections. However, the exact explanation had eluded researchers. As a possible explanation, scientists theorized that people more often gather inside during chilly weather and viruses survive better in low-humidity indoor air. However, it was unclear whether cold weather itself makes organisms more susceptible to infections.
In 2018, researchers discovered that cells in the nose produce so-called "extracellular vesicles" that attack and destroy bacteria.
"The best analogy that we have is a hornet's nest," Mansoor Amij, a pharmaceutical sciences professor at Northeastern University and one of the authors of the paper, said.
Like hornets, "extracellular vesicles" attack and destroy their biological enemy.
Scientists decided to carry on with further research and clarify whether "extracellular vesicles" would also attack and destroy viruses like they attack and destroy bacteria. They took pieces of nasal mucosa from volunteers who came to delete polyps in the nose. They used a test substance that mimicked viral infection. The experiment indicated that "extracellular vesicles" successfully attack and destroy viruses.
Also, they wanted to shed some light on the question of whether the temperature has some impact on the ferocity of "extracellular vesicles'" response. In order to do this, they cultivated nasal cells under different temperatures - one under 37 degrees Celsius and the other under 32C. Under regular body temperature conditions (up to 37C) "extracellular vesicles" were able to successfully destroy viruses. However, under reduced temperatures, fewer "extracellular vesicles" were produced and the attacks on viruses were less fierce.
This exactly explains why we “catch a cold”.
“There's never been a convincing reason why you have this very clear increase in viral infectivity in the cold months," said another author Benjamin Bleier, a surgeon at Harvard Medical School.
Researchers expect that their findings will help fight viruses, possibly including flu and even Covid.