Testing Backlogs May Cloud the True Spread of the Coronavirus

Though the coronavirus testing landscape continues to expand, most patient samples must still be routed through laboratories for processing, and the demand is once again straining supplies, equipment and trained technicians and causing shortages.

“It’s very important for people to be able to get the results in time, so they don’t continue infecting people,” said Pamela Martinez, an expert in disease dynamics at the Harvard T.H. Chan School of Public Health.

That has become increasingly essential, Dr. Martinez added, as mounting evidence has indicated that the virus can spread from people who don’t have symptoms. “Maybe if I take a test, but I don’t have many symptoms, I’m not going to take the same precautions,” she said.

Health workers typically advise their patients to quarantine at home while they await their test results, out of an abundance of caution. To the extent that one can, “The best thing to do is to act as if you’ve been infected” in this interim period, said Olivia Prosper, an infectious disease modeler at the University of Tennessee, Knoxville. But the longer people are forced to wait, the more difficult that advice is to follow — and the larger toll their absence from work or family responsibilities can take.

Additionally, negative results can be of little use if they are delivered after too long of a delay. Diagnostic testing, which searches for bits of the coronavirus’s genetic material, can only assess a person’s health status from the time the sample was taken, and can’t account for any subsequent exposures to the virus.