Why colds and flu are more prevalent in winter

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There’s chills in the air, and you know what that means. It’s cold and flu season, and everyone you know suddenly seems to be sneezing, sniffling, or worse. It’s as if those pesky cold and flu germs swirl with the first gust of winter weather.

Still, bacteria are present all year round. Remember the last summer cold. So why do people get colds, flu, and now he’s Covid-19 when it’s cold outside?

In what researchers call a scientific breakthrough, the scientists behind the new study may have discovered the biological reason why respiratory illnesses rise in the winter. It is known to damage the immune response that occurs.

Dr. Zara Patel, a rhinologist and professor of otolaryngology and head and neck surgery at Stanford University, said: University of California School of Medicine. She was not involved in her new research.

In fact, lowering the temperature inside your nose by just 9 degrees Fahrenheit (5 degrees Celsius) kills nearly 50 percent of the billions of virus- and bacteria-fighting cells in your nostrils, according to a study released Tuesday. When, Journal of Allergy and Clinical Immunology.

Dr. Benjamin Brier, rhinologist, director of the Massachusetts Eye and Ear Department of Otolaryngology and associate professor at Harvard Medical, said: school in Boston.

“It’s important to remember that these are in vitro studies, meaning they’re using human tissue in the lab to study this immune response, but it’s being done inside someone’s actual nose.” “Often, but not always, the results of in vitro studies are confirmed in vivo.”

To understand why this happens, Bleier and his team and co-authors mansur amidji, As chair of the pharmacy department at Northeastern University in Boston, he embarked on a forensic investigation.

Respiratory viruses and bacteria enter the body through the main entry point, the nose. Soon, the team found that the front of the nose detects bacteria before the back of the nose notices intruders.

At that point, the cells lining the nose start making billions of simple copies of themselves called extracellular vesicles (EVs).

“EVs can’t divide like cells, but they’re like tiny versions of cells specifically designed to kill these viruses,” said Bleier. “The EVs act as decoys, so when you inhale the virus, it sticks to these decoys instead of sticking to the cell.”

These “Mini Me’s” are expelled by the cells into the snot (yes, snot) and stop there. It invades bacteria before they reach their destination and multiply.

“It’s one, if not the only part of the immune system that fights bacteria and viruses to leave the body and fight them before they can actually enter the body,” Bleier said.

Once produced and dispersed in nasal secretions, billions of EVs begin swarming the predatory bacteria, Breyer said.

“What happens if you kick a wasp nest? “It attacks,” he said.

A study found that when challenged, the nose increased extracellular vesicle production by 160%. The surface of EVs has far more receptors than the cells of origin, increasing the virus-blocking ability of billions of extracellular vesicles in the nose.

“Imagine a receptor as a little arm sticking out, trying to grab onto a virus particle as you suck it in,” says Briar. “And the surface of each vesicle has up to 20 times more It had receptors and turned out to be very sticky.”

Cells in the body also contain virus killers called microRNAs that attack invading bacteria. However, the study found that nasal EVs contained 13 times more microRNA sequences than normal cells.

As such, the Nose comes into battle armed with a few extra superpowers. But what happens to these benefits when cold weather hits?

To find out, Bleier and his team exposed four study participants to a temperature of 40 degrees Fahrenheit (4.4 degrees Celsius) for 15 minutes and measured their intranasal conditions.

“What we discovered is that exposure to cold air can lower the temperature of the nose by as much as nine degrees Fahrenheit, and that’s all of these three immune benefits that the nose has.” is enough to virtually knock out ,” said Bleier.

In fact, a slight chill on the tip of the nose was enough to take about 42% of the extracellular vesicles out of the fight, Bleier said.

“Similarly, there is almost half the amount of these killer microRNAs within each vesicle, which can reduce the number of receptors in each vesicle by up to 70%, thus significantly reducing stickiness. ‘ he said.

What effect would that have on your ability to fight off colds, flu, and Covid-19? Briar says it halves the immune system’s ability to fight off respiratory infections.

After all, the pandemic has given us exactly what we need to fight off the cold and keep our immunity high.

“Masks not only prevent you from breathing the virus directly, they are like wearing a sweater over your nose.

Patel also agrees: Another reason to wear a mask!

Bleier hopes to see the development of topical nasal medicines based on this scientific discovery in the future. These new drugs “will essentially trick the nose into thinking it’s just seen the virus,” he said.

“By having that exposure, all these extra wasps fly around in the mucus and protect you,” he added.