It’s a common cheat in the days of pandemic. People keep a mask over their mouth but keep their nose uncovered, perhaps guessing coronavirus transmission most likely occurs through the mouth.
But new research at the University of North Carolina throws that idea on its head, finding that the novel coronavirus more easily infects the nose. In fact, the study shows the virus first becomes firmly established there, seeding the lung infections that can later be calamitous.
Investigators say this is strong evidence showing why it is essential to cover both your nose and mouth rather than what’s known as half-masking.
The researchers were trying to understand how the coronavirus comes to infect our airways and gets into our lungs. Their work showed nasal-lining cells became much more abundantly infected than cells of the throat, bronchia and lungs.
They also found that the ACE2 [ace-two] receptor — a protein through which the coronavirus enters the body — is more commonly found in the nose than other parts of the respiratory system.
Scientists also looked for clues in the pattern of coronavirus infection in the lungs. They thought that if someone got COVID-19, the disease caused by the coronavirus, by breathing it through the air, the pattern of infection in the lungs would be evenly distributed.
Instead, they found patches of infection next to healthy lung tissue. This supports the idea that the lungs become infected when mucus and other liquids are aspirated downward from the upper-respiratory tract.
Researchers say wearing a mask over the mouth and nose makes good sense. It protects the wearers as much as it does those around them.