The Covid-19 is said to have arrived in the United States earlier than expected

Researchers from the Centers for Disease Control and Prevention (CDC) conducted a survey of 7,000 blood bags. They were collected by the American Red Cross between December 13, 2019 and mid-January 2020. This was well before the official filing of the first case of Covid-19 in the United States, which dates back to January 20, 2020. Now 106 samples out of 7,000 were labeled positive for antibodies associated with Covid-19.

Note that the samples are from nine US states. More than half of the patients who test positive for the disease are from Massachusetts, Michigan, Connecticut, Rhode Island, Iowa, and Wisconsin. The remaining 39 are from Washington, California and Oregon.

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The results of this new study question the date when the virus really started spreading on American soil.

False positives or positive cases?

As a reminder, the Chinese state reported the first cases of this disabling pneumonia at the end of December 2019. It was in Wuhan, the capital of Hubei.

It should be noted that a positive test for antibodies against coronavirus only suggests infection with the Cov-2 of SARS. The possibility of false positives between samples cannot be excluded. They are mainly due to the host’s response to other types of coronavirus.

So to refine their results, the CDC researchers conducted further tests. They analyzed the collected samples to look for responses to SARS Cov-2 antibodies. Finally, 84 of the 90 analyzes are positive. “The results make it very unlikely that all samples are false positives”, they concluded. In other words, the team is almost certain that a large number of these patients are infected with Covid-19.

Also read: Covid-19 vaccine, the 5 steps recommended by the HAS

There are still some gaps to be filled

Dr. George Rutherford, an epidemiologist from the University of California who is also a professor of biostatics in San Francisco, pointed out the limitations of the study. For him, in addition to the possibility of a cross-reaction with other types of coronavirus, the research has another flaw. This is data about the exact places where people who tested positive contracted the virus. For example, the study questionnaire does not take into account possible travel abroad.

Also read: We know who will receive the first doses of the anti-Covid-19 vaccine in the United States

Dr. Rutherford argued that more studies are needed to verify these results. In particular, he recommended searching for Cov-2 genetic material from SARS on these positive samples. This should be based on analysis of the saliva, blood, and tissue of the first Americans to test positive.

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