A new study conducted by Penn State researches estimates the number of early coronavirus cases in the United States may have been more than 80 times greater and doubled nearly twice as fast as reported.

Researchers estimated the detection rate of symptomatic coronavirus cases using the Centers for Disease Control and Prevention’s (CDC) influenza-like illnesses (ILI) during a three-week period in March.

“We analyzed each state’s ILI cases to estimate the number that could not be attributed to influenza and were in excess of seasonal baseline levels,” Justin Silverman, assistant professor in Penn State’s College of Information Sciences and Technology and Department of Medicine, said. “When you subtract these out, you’re left with what we’re calling excess ILI — cases that can’t be explained by either influenza or the typical seasonal variation of respiratory pathogens.”

Researchers also discovered the excess ILI had a nearly perfect correlation with the spread of the coronavirus pandemic. The size of the observed increase in excess ILI corresponds to more than 8.7 million new cases in the last three weeks of March.

Excess ILI seems to have peaked in mid-March since fewer patients with mild symptoms sought medical care and states implemented interventions to lower transmission rates.

“Our results suggest that the overwhelming effects of COVID-19 may have less to do with the virus’ lethality and more to do with how quickly it was able to spread through communities initially,” Silverman explained. “A lower fatality rate coupled with a higher prevalence of disease and rapid growth of regional epidemics provides an alternative explanation to the large number of deaths and overcrowding of hospitals we have seen in certain areas of the world.”

Earlier this month, a different group of Penn State researches found handheld ultraviolet lights could prove useful in killing the coronavirus and disinfected surfaces.

You can read more about the research, including the full publication, here.