A team of researchers looked at the number of people who went to doctors or clinics with flu-like illnesses and were never diagnosed with coronavirus, influenza or any of the other viruses that usually circulate in the winter.
“The findings support a scenario where more than 8.7 million new SARS-CoV-2 infections occurred in the United States in March and estimate that more than 80% of these cases remain unknown as the epidemic spread quickly,” Justin Silverman said. Penn State University, Alex Washburne of Montana State University and his colleagues at Cornell University and elsewhere wrote.
Only 100,000 cases were officially reported during this period, and the United States still reports only 2.3 million cases by Monday. But there was a shortage of corona test kits at the time.
The team used data collected from each state by the U.S. Centers for Disease Control and Prevention for flu-like illness. The CDC uses this data to monitor the annual seasonal flu epidemic. He asks doctors to report all cases of people coming for treatment for fever, cough and other flu-induced symptoms.
“We found a clear, abnormal increase in influenza outpatients during the COVID-19 epidemic associated with the outbreak in many states in the United States,” Silverman and colleagues wrote.
“The increase in outpatients with influenza-free ILI was much higher than the number of confirmed cases in each case, providing evidence of a large number of possible COVID-19 symptomatic cases that remained undiagnosed.”
These were people who showed up at a doctor’s office or clinic with symptoms. Most people with Covid-19 have probably never sought treatment for it.
“The ILI wave across the United States seemed to peak during the week that began on March 15 and then fell in many states next week. Notable exceptions are New York and New Jersey, two of the most affected states. from the epidemic, which had not begun to decline until the week ended March 28, “the group wrote.
The researchers were unable to measure each case, so they conducted a series of calculations to make sure their data matched what was known to the population and the annual flu epidemic, as well as the hard data collected from real patient mock tests. They also took into account the growing evidence that people began to avoid hospitals, clinics and doctor’s offices when it was clear that there was a pandemic after the start of the pandemic locks.
“If 1/3 of patients infected with SARS-CoV-2 in the United States sought treatment, this increase in ILI would account for more than 8.7 million new SARS-CoV-2 infections in the United States during the three-year period. weeks from March 8 to March 28, 2020, “the researchers wrote.
Cases fell after that. “We’ve seen this huge peak that ended on March 22 in most places,” Silverman told CNN. Since then, cases have been declining, he said – but the data collected by the group has not been included for the past two weeks.
The team is now working to try to approach the pandemic in real time. The data from the CDC comes about two weeks after people visit their doctor. They hope that their approach – called subscription monitoring – could complement data collected from actual tests. “In a dream world, everyone who comes will have a test. We could get a full field of application of pandemic,” Washburne told CNN.