FRIDAY, March 19 2021 (HealthDay News) — It took a “perfect storm” for the COVID-19 pandemic to occur, according to researchers who examined when and how the virus first emerged in China.
They found that the new coronavirus didn’t infect the first human until October 2019 at the earliest, and that it was bad luck and the crowded setting of the Huanan seafood market in Wuhan — where the pandemic appears to have started — that set the virus on its worldwide spread, CNN reported.
The study was published Thursday in the journal Science.
“It was a perfect storm — we know now that it had to catch a lucky break or two to actually firmly become established,” study co-author Michael Worobey, a professor of evolutionary biology at the University of Arizona, told CNN.
“If things had been just a tiny bit different, if that first person who brought that into the Huanan market had decided to not go that day, or even was too ill to go and just stayed at home, that or other early super-spreading events might not have occurred. We may never have even known about it.”
The research team used molecular dating, which involves assessing the rate of ongoing mutations to calculate how long the virus has been around. They also ran computer models to show when and how it could have spread, and how it did spread.
“Our study was designed to answer the question of how long could SARS-CoV-2 have circulated in China before it was discovered,” said researcher Joel Wertheim, an associate professor in the San Diego School of Medicine’s Division of Infectious Diseases and Global Public Health.
“To answer this question, we combined three important pieces of information: a detailed understanding of how SARS-CoV-2 spread in Wuhan before the lockdown, the genetic diversity of the virus in China, and reports of the earliest cases of COVID-19 in China. By combining these disparate lines of evidence, we were able to put an upper limit of mid-October 2019 for when SARS-CoV-2 started circulating in Hubei province.”
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