An international team of scientists has found evidence that SARS-CoV-2 infects oral cells.
Earlier it became known that the upper respiratory tract and lungs are the main foci of SARS-CoV-2 infection. However, as a result of the new study, the authors have found signs that the virus can infect cells in other parts of the body, such as the digestive system, blood vessels, kidneys and mouth.
The fact that the virus can infect multiple areas of the body will help explain the wide range of symptoms that COVID-19 patients experience.
What’s more, the findings indicate that the mouth may play a role in the transmission of SARS-CoV-2 to the lungs or digestive system through virus-laden saliva.
Researchers examined oral tissue in healthy people to identify areas of the mouth susceptible to SARS-CoV-2 infection.
RNA of two key proteins for entry – the ACE2 receptor and the TMPRSS2 enzyme – has been found in salivary gland cells and oral tissues. This indicates an increased vulnerability, as the virus is believed to need both input proteins in order to gain access to cells.
In addition, in the tissue of the salivary glands of one of the deceased people, as well as of a person who is currently suffering from an acute form of COVID-19, scientists found specific sequences of viral RNA: they indicated that cells are actively making new copies of the virus.
More research will be needed to confirm these findings in a wider group of people and to determine the exact nature of how our mouth spreads SARS-CoV-2 and transfers it outside the body.