COVID-19 Was In PA Long Before Tests Confirmed It, New Study Says

PENNSYLVANIA — New research indicates that the coronavirus first broke out in Pennsylvania and four other states weeks before the first positive test results were confirmed in March 2020.

The study, a collaboration of medical experts from across numerous universities and federal agencies, shows that a person tested positive in Pennsylvania on Feb. 15, 2020. The previously first known cases in the state were announced by the Department of Health on March 6, 2020.

Study authors said the new findings supported existing hypotheses that the virus was "likely" spreading in Pennsylvania in early February.

The bloodwork of more than 24,000 persons was analyzed from all 50 states from Jan. 2 to March 18. Seven of these test results came back positive in five states — Pennsylvania, Mississippi, Wisconsin, Illinois and Massachusetts — indicating the virus was present to some degree long before it was publicly confirmed.

Of interest, study authors noted, was that these early cases were found far away from early hot spots of the virus such as New York City and Seattle, locations that had once been considered the chief vectors of COVID-19 into the country.

The earliest positive test found in the nationwide study was in Illinois all the way back to Jan. 7, 2020. Because it takes a few weeks for test results to be detectable, this means that infection could have occurred as early as Dec. 24, 2019.

But even though the virus was present in these states earlier than originally confirmed, it still appears unlikely it was widespread at that point.

"Was the cold you had in Jan - Mar 2020 #COVID19? I don't know. But given the very low prevalence (9 out of 24K) it is likely it wasn't," shared Dr. Keri N. Althoff, the epidemiologist who served as lead author on the study.

The study used health data from the National Institute of Health's "All of Us" research program, which aims to gather information from 1 million people around the nation in order to better inform health policy.

The study in its entirety can be found online here.