Cold air is associated with increased viral infection because youve essentially lost half of your immunity just by that small drop in temperature . When under attack the nose increases production of extracellular vesicles or ‘mini versions’ of cells designed to go and kill these viruses . These mini versions of cells act as decoys so now when you inhale a virus the virus sticks to these decoys instead of sticking to the cells . These are in vitro studies meaning although it is using human tissue in the lab to study this immune response it is not a study being carried out inside someones actual nose . The study published in The Journal of Allergy and Clinical Immunology found that when exposed to four minutes to four degree temperatures and then measured inside their nasal cavities the nose was measured measured to take nearly of the extracecellic vesicle out of the nose to fight out the coldness in the nose . In fact reducing the temperature inside the nose can drop by as much as . degrees Fahrenheit degrees Celsius kills almost of the billions of helpful bacteriafighting cells and viruses in the nostrils . The researchers say it is important to remember that these are in the in vitro Studies meaning that although it was using human tissues it is . not a research being carried . out inside the nasal cavity . The nose is not an effective immune response . It is not the immune response to the nose. It is an effective way to protect itself from the cold. It has many more receptors on their surface. The researchers have no direct access to the nasal mucus. to the surface. It was not an ineffective immune systems. It does not have direct control of the immune systems in the back of the nasal passages. The scientists say it does not necessarily provide an effective