Clues in Europe
Three days before Patient S01’s symptoms began, on Dec. 5, 2019, an oral swab was taken from a 4-year-old boy outside of Milan who was suspected of having measles. Months later, it tested positive for coronavirus RNA. The case, outlined in the Emerging Infectious Diseases journal, is one of several European studies suggesting the virus may have circulated undetected overseas for weeks, even months.
...A team from France’s National Institute for Health and Medical Research and other institutes retrospectively examined over 9,000 serum samples banked as part of a public health project from November 2019 through March 2020.
“We found antibodies in the first week of November, but we had no money to go back further in time,”
... the most controversial study: In a paper published in November, researchers in Italy reported traces of the coronavirus in September 2019, ...nearly 1,000 blood samples collected in 2019 from a cancer-screening trial. They reported more than 10 percent containing coronavirus antibodies, including samples from September 2019.
...they might have detected a “less transmissible” strain that could circulate without sparking a major outbreak.
Some doctors doubt the virus could have circulated unnoticed for so long, and say antibody tests can produce false positives.
...suggests small-scale earlier transmission was possible. In a paper published in Science magazine in April, scientists simulated a SARS-CoV-2 outbreak 1,000 times, and found it fizzled out more than two-thirds of the time. Joel Wertheim, an evolutionary biologist at the University of California at San Diego involved in the study, said their team estimated the Wuhan outbreak began in November, but couldn’t rule out earlier isolated clusters.
...brought to Wuhan from abroad. This theory has found little support from scientists in other countries, partly because of the genetic similarity between SARS-CoV-2 and known bat coronaviruses from China’s south.
...October 2019. It would have been easy to miss the first cases: China was in the thick of its worst flu season in more than a decade. Official statistics show that by November 2019, there were five times the number of influenza cases across China compared to a year earlier. By December, it was ninefold.
...Military World Games. It was only one of a string of international events in Wuhan that autumn....
...One Wuhan resident, Stella Zhou, recalled to The Washington Post that she heard talk of a mysterious pneumonia at a child-care center on Dec. 8, 2019, the same day Patient S01 fell ill, and nearly a month before the official announcement.
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