Thursday 17th June 2021
Antibodies prove it
Sars-CoV-2 was already in the USA in 2019
In order to find out how the coronavirus pandemic came about, researchers in the USA are examining many stored blood samples for antibodies – and they find them. Two people in the USA must have been infected with Sars-CoV-2 by the end of 2019.
Sars-CoV-2 most likely arrived in the USA in December 2019, a few weeks earlier than previously assumed. This is what researchers from the Bloomberg School of Public Health in Baltimore have found. The results come from an examination of more than 24,000 blood samples. According to the researchers, Sars-CoV-2 antibodies were discovered in nine samples, which suggest an earlier infection than previously assumed.
The exciting thing about it: Seven of these nine study participants had already had their blood drawn before infections even officially occurred in the respective state. These early positives came from the states of Illinois, Massachusetts, Wisconsin, Pennsylvania, and Mississippi. Previously, it was assumed that Sars-CoV-2 infections would spread across the country from Seattle and New York.
The day of the blood sample is crucial
The total of 24,079 blood samples examined came from participants in the so-called “All Of Us” biobank studies. They were drawn across the country from January 2 to March 18, 2020, before any further blood draws were stopped by the lockdown. The earliest positive blood sample was taken in Illinois on January 7, 2020, and the next on January 8 in Massachusetts. In Illinois, there were two more cases on January 20 and 22, according to the results. The other positive blood draws were on February 3 in Wisconsin, February 15 in Pennsylvania, and March 6 in Mississippi.
Keri Althoff’s research team assumes that the two study participants with the earliest samples were most likely infected with Sars-CoV-2 as early as December 2019. The reason: it usually takes one to two weeks between the infection and the formation of antibodies.
In their search for antibodies, the researchers relied on double testing. This should minimize false positive results. They started by examining the March 2020 samples with the Elisa test and then worked their way towards the past. The first antibody test reacted positive in a total of 147 blood samples. In the control test with Euroimmun, nine antibody-positive blood samples could still be identified. Both tests are approved in the USA and are considered to be very reliable.
Since the researchers did not contact the people concerned for their investigation, they also have no way of knowing whether the people had previously been in China and infected there or whether they had already contracted other people in the United States.
The results of the study, which were published in the journal “Clinical Infectious Diseases”, reinforce the results of an earlier examination of blood donations. Here, too, there were indications that Sars-CoV-2 weeks earlier than January 20, 2020, the day of the first confirmed case, was introduced into the USA.