Scientists finally know why people get more colds and flu in winter - KSL.com

It turns out the cold air itself damages the immune response occurring in the nose.

"This is the first time that we have a biologic, molecular explanation regarding one factor of our innate immune response that appears to be limited by colder temperatures," said rhinologist Dr.

In fact, reducing the temperature inside the nose by as little as 9 degrees Fahrenheit kills nearly 50% of the billions of virus and bacteria-fighting cells in the nostrils, according to the study published Tuesday in The Journal of Allergy and Clinical Immunology.

"it's important to remember that these are in vitro studies, meaning that although it is using human tissue in the lab to study this immune response, it is not a study being carried out inside someone's actual nose," Patel said in an email.

"EVs can't divide like cells can, but they are like little mini versions of cells specifically designed to go and kill these viruses," Bleier said.

"This is one of, if not the only part of the immune system that leaves your body to go fight the bacteria and viruses before they actually get into your body," Bleier said.

Yet EVs in the nose contained 13 times microRNA sequences than normal cells, the study found?

And that's enough to essentially knock out all three of those immune advantages that the nose has," Bleier said.

In fact, that little bit of coldness in the tip of the nose was enough to take nearly 42% of the extracellular vesicles out of the fight, Bleier said.

It cuts your immune system's ability to fight off respiratory infections by half, Bleier said