The SARS-CoV-2 virus infects cells in the mouth and can be transmitted via saliva, according to research from the National Institutes of Health and University of North Carolina at Chapel Hill published March 25 in Nature.
"Our study shows that the mouth is a route of infection as well as an incubator for the SARS-CoV-2 virus that causes COVID-19," said Kevin M. Byrd, DDS, PhD, one of the lead researchers and the American Dental Association Science and Research Institute's Anthony R. Volpe Research Scholar.
Scientists exposed saliva from eight people with asymptomatic COVID-19 to healthy cells grown in a dish. Saliva from two volunteers caused the healthy cells to become infected, meaning it is possible for asymptomatic people to transmit the virus to others via saliva.
The researchers collected saliva from 35 separate volunteers with mild or asymptomatic COVID-19 and found those who experienced symptoms were more likely to report a loss of taste and smell if they had virus in their saliva.
The research also suggests the mouth may play a role in transmitting SARS-CoV-2 to the lungs or digestive system through saliva that contains the virus from infected oral cells.
The findings still need to be confirmed in a larger group of people, and more research is needed to determine the exact nature of infection and transmission.