The coronavirus was likely present in Massachusetts in late December 2019, more than a month before the state's Department of Public Health reported the first official case.
Researchers at the National Institutes of Health analyzed more than 24,000 blood samples taken between Jan. 2 and March 18, 2020, and found signs that people in the Bay State might have had COVID as early as December of 2019.
COVID antibodies were found in some samples taken as early as Jan. 8 in Massachusetts. Since antibodies take around two weeks to form, that leads researchers to believe those people were infected in December at the latest.
So far research, researchers say they've only found those early antibodies in five states; Massachusetts, Mississippi, Pennsylvania, Illinois and Wisconsin.
Researchers are unsure if those infected individuals caught COVID from overseas or from someone in their own community. Regardless, researchers say it underlines the need for more testing as early as possible in potential future pandemics.