◆ Tracking viral loads helps treat virus patients.

As COVID-19 patients flood into hospitals nationwide, doctors are facing an impossible question. Which patients in the ER are more likely to deteriorate quickly, and which are most likely to fight off the virus and to recover?

As it turns out, there may be a way to help distinguish these two groups, although it is not yet widely employed. Dozens of research papers published over the past few months found that people whose bodies were teeming with the coronavirus more often became seriously ill and more likely to die, compared with those who carried much less virus and were more likely to emerge relatively unscathed.

The results suggest that knowing the so-called viral load — the amount of virus in the body — could help doctors predict a patient’s course, distinguishing those who may need an oxygen check just once a day, for example, from those who need to be monitored more closely, said Dr. Daniel Griffin, an infectious disease physician at Columbia University in New York.

Tracking viral loads “can actually help us stratify risk,” Griffin said. The idea is not new: Managing viral load has long formed the basis of care for people with HIV, for example, and for tamping down transmission of that virus.

Little effort has been made to track viral loads in COVID-19 patients. This month, however, the Food and Drug Administration said labs might report not just whether a person was infected with the coronavirus, but an estimate of how much virus was carried in their body.

This is not a change in policy — labs could have reported this information all along, according to two senior FDA officials who spoke on condition of anonymity because they were not authorized to speak publicly.

Still, the news came as a welcome surprise to some experts, who have for months pushed labs to record this information.

“This is a very important move by the FDA,” said Dr. Michael Mina, a public health researcher at the Harvard T.H. Chan School of Public Health.