The number of coronavirus cases in the US USA During March it may have been 80 times higher than the original estimates, representing more than 8.7 million new cases that health officials and the public never knew existed, according to a new study.
Researchers led by epidemiologists at Penn State University studied surveillance data on influenza-like illnesses from the US Centers for Disease Control and Prevention. USA And they noticed a big increase in cases that month, they reported Monday in the journal Science Translational Medicine.
“The findings support a scenario in which more than 8.7 million new SARS-CoV-2 infections appeared in the US during March and estimate that more than 80% of these cases remained unidentified as the Outbreak spread quickly, “wrote Justin Silverman of Penn State, Alex Washburne of Montana State University and colleagues at Cornell University and elsewhere, CNN reported.
At the time, when there was a shortage of coronavirus test kits, around 100,000 cases of the disease had been officially reported. As of Tuesday, about 2.3 million cases and more than 120,000 deaths have been reported.
“We analyzed cases from each state (flu-like illness) to estimate the number that could not be attributed to flu and that exceeded seasonal reference levels,” said Silverman, an assistant professor at the College of Information Sciences and Penn State Technology and the Department of Medicine.
“When you subtract this, you’re left with what we call excess ILI: cases that cannot be explained by either the flu or the typical seasonal variation of respiratory pathogens,” he said in a press release.
“At first I couldn’t believe our estimates were correct,” added Silverman. “But we found that deaths in the US had doubled every three days and that our estimate of the infection rate was consistent with the doubling of three days since the first observed case was reported in the state of Washington on January 15. “
The researchers found that excess in cases of flu-like illness, or ILI, showed an almost perfect correlation with the spread of the coronavirus in the United States.
“This suggests that the ILI data is capturing COVID cases, and there appears to be a much larger undiagnosed population than originally thought,” Silverman said.
The researchers estimated infection rates for each state, noting that those with the highest infection rates per capita also had the highest per capita rates of an increase in excess ILI.
Their data showed rates much higher than those initially reported but closer to those found once states began completing antibody tests for the disease.
In New York, for example, the researchers’ model suggested that at least 9 percent of the state’s population was infected in late March. After the state conducted antibody tests on 3,000 people, they found an infection rate of 13.9 percent, or 2.7 million New Yorkers.
“The increase in ILI across the United States seemed to peak during the week that began on March 15 and subsequently decreased in numerous states the following week; notable exceptions are New York and New Jersey, two of the states that were most affected by the epidemic, which had not begun to subside in the week ending March 28, “the researchers wrote.
The findings suggest another way of thinking about the outbreak.
“Our results suggest that the overwhelming effects of COVID-19 may have less to do with the lethality of the virus and more to do with how quickly it initially spread through communities,” Silverman said.
“A lower death rate coupled with a higher prevalence of disease and a rapidly growing regional epidemic provides an alternative explanation for the large number of hospital deaths and overcrowding that we have seen in certain areas of the world,” he added.
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