A research study run by the US National Institutes of Health has turned up evidence of possible coronavirus infections in the United States as early as December 2019, weeks before the first documented infection in this country.

Iran PressAmerica: The new report, published in the journal Clinical Infectious Diseases, bolsters earlier studies indicating that the virus entered the country under the radar and may have been spreading in the first two months of 2020, well in advance of warnings to that effect from the Centers for Disease Control and Prevention.

A volunteer in Illinois who gave blood on Jan. 7, 2020 — in a study unrelated to the emergent virus — tested positive for antibodies to SARS-CoV-2, according to the NIH report. It noted that the antibodies typically take 14 days, on average, to develop, and this “suggests the virus may have been present in Illinois as early as December 24, 2019.”

This and other studies could nudge the timeline of the pandemic’s effect on the United States to earlier dates. The first case of a coronavirus infection in the United States was confirmed Jan. 20, 2020, in a patient in Everett, Wash., who had traveled from Wuhan, China, and had become symptomatic Jan. 14.

But the CDC did not identify community spread of the virus — meaning, infections unrelated to travel from China — until Feb. 26. The NIH report states that the CDC testing guidelines early in the pandemic had a narrow focus: Only people who had been in contact with a person confirmed to have an infection, or who had traveled to an area known to have coronavirus transmission, were advised to be tested.

Elements of that guidance “may have been in place too long, obscuring the geographic spread of SARS-CoV-2 found in our results.”

The volunteers had given blood samples as part of NIH’s “All of Us” research program, a multiyear effort to advance “precision medicine” by gathering detailed health data from a large and diverse group of people. The program has enrolled and collected samples from about 280,000 people so far and has a goal of at least 1 million participants. Precision medicine tailors health care for individuals and their circumstances, rather than a one-size-fits-all approach.

As a result, NIH has a vast supply of blood samples capable of being scrutinized — in this case for evidence of coronavirus infections. The researchers employed two distinct antibody tests on 24,000 subjects who gave blood between Jan. 2 and March 18, 2020.

Nine of those people came up positive on both tests for SARS-CoV-2 antibodies. Seven of those gave blood in five states — Illinois, Massachusetts, Mississippi, Pennsylvania and Wisconsin — before the first official cases in those states.

The report noted briefly that, of the nine people who tested positive, seven were from racial or ethnic minorities: five were Black and two were “Hispanic, Latino or Spanish.” The pandemic revealed the heightened vulnerability of people of color in the United States to exposure to the coronavirus in part because of their overrepresentation as essential workers, and although the data set in this study was small, it carried a possible signature of that disparity.

The report states, “Although the numbers are limited, these findings reinforce scientific hypotheses of the impact of social factors on viral circulation, including structural discrimination against racial and ethnic minority groups.”

Another striking finding is that no positive test results were found in California, New York or Washington state, which were known as the initial entry points in the country for the virus.