Get all the latest news on coronavirus and more delivered daily to your inbox. Sign up here.
"What was somewhat surprising to see is only one-third of patients who required hospitalization presented with a fever," senior study author Karina Davidson told FOX Business.
The study looked at the outcomes of patients at Northwell Health, New York's biggest health system, between March 1 and April 4. It's the most comprehensive U.S. study published so far according to Davidson, who directs the Center for Personalized Health at Feinstein Institutes for Medical Research, Northwell's science wing.
The low number of patients who had fevers when first assessed could undercut hopes that instituting widespread temperature checks will allow the U.S. to reopen its economy.
"We should not be checking fever alone," Davidson said. "That is not sufficient to know when someone has a COVID-19 infection."
A Smithfield Foods plant in Sioux Falls, South Dakota, became one of the biggest coronavirus hotspots in the U.S. despite installing thermal imaging systems, according to a Centers for Disease Control & Prevention memo.
The memo recommends individual temperature checks "using a temporal, tympanic, or oral thermometer with a probe cover" instead.
As the U.S. economic slowdown caused by coronavirus continues to take its toll, companies including Amazon and Tyson Foods are touting their temperature check policies after employees at many of their facilities tested positive for the virus.
Amazon said April 4 that employees will be temperature checked as soon as they arrive at work. Anyone with a fever above 100.4 degrees will be sent home, which is a CDC recommendation.