To the known risk factors for developing severe COVID-19—age, male sex, or any of a series of underlying conditions—a new study adds one more: high levels of the virus in your saliva. Standard COVID-19 tests sample the nasal passage. But several new tests look for SARS-CoV-2, the pandemic coronavirus, in saliva, and the new work finds a striking correlation between high virus levels there and later hospitalization or death. If the results are confirmed, saliva tests could help doctors prioritize which patients in the early stages of the disease should receive medicines that drive down levels of the virus.
“I thought it was pretty striking,” says Shane Crotty, a virologist at the La Jolla Institute for Immunology, who was not involved with the research. Crotty notes the results suggest virus levels in saliva reflect viral load deep in the lungs, where the disease does much of its damage in severe cases. “That is a fundamentally valuable insight,” Crotty says.