November 17, 2020 -- The novel coronavirus was circulating in Italy as early as September 2019, according to a new study by the country’s national cancer institute, which looked for the virus in blood samples in Milan.

That means the coronavirus may have spread beyond China months earlier than scientists originally believed, according to Reuters.

According to the study, Italy’s first documented COVID-19 patient was on Feb. 21 in a small town near Milan. However, the researchers knew the virus was likely circulating before that, so they analyzed blood samples of people enrolled in a lung cancer screening trial between September 2019 to March 2020.

They found COVID-19 antibodies in 111 of 959 people, or nearly 12%. About 14% of the positive blood samples were drawn in September, with a cluster of cases (about 30% of the positives) popping up during the second week of February.

“This study shows an unexpected very early circulation of SARS-CoV-2 among asymptomatic individuals in Italy several months before the first patient was identified,” the authors wrote. “Finding SARS-CoV-2 antibodies in asymptomatic people before the COVID-19 outbreak in Italy may reshape the history of pandemic.”

The World Health Organization said Monday that it would contact the researchers and review the results, Reuters reported. The organization may further analyze samples and verify the data, and the Italian researchers plan to continue their work as well.

If the initial history of the pandemic shifts, public health officials may need to consider new screening tools to test people who don’t have COVID-19 symptoms. Better screening could contain future waves of the pandemic and asymptomatic spread, the authors wrote.

“The new coronavirus can circulate among the population for a long time and with a low rate of lethality, not because it is disappearing, only to surge again,” Giovanni Apolone, one of the co-authors, told Reuters.

WebMD Health News Brief

Sources

Reuters, “Researchers find coronavirus was circulating in Italy earlier than thought.”

Tumori Journal, “Unexpected detection of SARS-CoV-2 antibodies in the prepandemic period in Italy.”

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