Why winter is associated with more colds and flu

Why winter is associated with more colds and flu


The fall season has come and gone, and winter holiday music and festive decor are all around us. In most parts of the country, temperatures have plummeted. Some places have even experienced the first snowfall.

This time of year is also known as cold and flu season. But why do we experience more colds and flu when temperatures drop?

Scientists say part of the reason we contract more respiratory illness in the winter is because the cold air damages the immune response in our noses.

According to a new study from Harvard Medical School, a temperature drop of as little as 9 degrees Fahrenheit kills nearly half the bacteria-battling cells and viruses in the nose.

Respiratory viruses and bacteria invade the body through the nose. The front of our nose detects the germ, ensuring the back of the nose is on high alert for the intruder. Cells lining the nose instantly create billions of simple copies of themselves called extracellular vesicles [vess-ih-kuhls]. These sticky cells, having smothered the invading viruses and bacteria, are discharged through nasal mucus. Hopefully into a tissue.

The study’s authors, from Harvard Medical School, say this nose army is one of the only parts of the human immune system that leaves the body to fight bacteria and viruses.

The study found that the nose increases its production of extracellular vesicles by 160% during such invasions. Our cells also contain microRNA, a viral killer that attacks invading germs.

Unfortunately, cold weather is kryptonite to that brave cell army, which fizzles when your nose gets too frigid.

This winter, bundle up to protect yourself. Your nose can’t do it for you.

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