8.7 million Americans may have been infected with MARCH in March MARCH, but 80% were never diagnosed
Millions of Americans may have contracted the new coronavirus at the onset of the pandemic, but the majority were never diagnosed, a new study suggests.
Researchers at Penn State University found that as many as 8.7 million people in the United States were infected with COVID-19, the virus-caused disease, in March.
However, more than three-quarters of them – 80 percent – were never confirmed to have the virus due to the limited availability of tests and asymptomatic people who never sought medical attention.
Researchers saw a wave of influenza-like illness in the United States (above). In New York (top left), 10% of all flu-like cases could not be attributed to flu or other seasonal viruses
If only a third of all non-influenza cases in the US were actually coronavirus, that would mean 8.7 million people are infected with the virus. Pictured: Nurses care for a coronavirus patient at the ICU at the Regional Medical Center in San Jose, California, May 21
For the study, published in the journal Science translational medicine, the team looked at data from people who visited doctor’s offices or clinics with influenza-like diseases (ILI).
These patients were never diagnosed with seasonal flu, coronavirus, or other typical winter viruses.
Researchers saw a wave of cases with symptoms like flu, such as fever and cough, in March 2020, but that could not be attributed to the flu.
This was true for several states, including Colorado, Louisiana, Maryland, New Jersey, New York, Oregon, Pennsylvania, and Washington.
For example, in the fourth week of March 2020, New York saw double the number of non-influenza ILIs.
In addition, more than 10 percent of all outpatient visits in the state could not be explained by flu or other seasonal respiratory viruses.
The team estimated that if only a third of all patients in these states were infected with the virus, the ILI peak would mean that there would be about 8.7 million people with coronavirus in the United States from March 8 to March 28.
But by the end of the investigation period, only about 160,000 cases had been confirmed in America.
This means that according to the Penn State model, about 2.6 percent of the total U.S. population was infected in March, not 0.04 percent.
Researchers say there are several reasons why up to 80 percent of patients have never been diagnosed.
During this time, there was limited availability of tests and a large number of false negatives from the available kits.
In addition, many people were asymptomatic or, if they had symptoms, they did not always seek medical attention.
“We found a clear, abnormal wave of outpatient influenza-like disease (ILI) during the COVID-19 epidemic that correlated with the progression of the epidemic in multiple states in the US,” the authors wrote.
“The increase in non-influenza ILI outpatients far exceeded the number of confirmed cases in each state, demonstrating large numbers of likely symptomatic COVID-19 cases that went unnoticed.”
In the U.S., there are currently more than 2.3 million confirmed cases of the virus and more than 120,000 deaths.