The first confirmed case was announced by federal authorities on January 21, a thirties who returned on January 15 from the Wuhan area of China who had no severe symptoms and had contacted a doctor himself. The first official “local” contagion was at the same time in Chicago between two spouses.
The late discovery that people started dying in early February implies that there were probably many cases on the west coast of the United States in early or mid-January, and that the current official death toll of 45,000 is below reality.
This is “not really a surprise,” said Alessandro Vespignani of Northeastern University in Boston, AFP, who recalls that epidemiological models had calculated that transmissions had probably started outside China in January and February.
The official assessment, for the beginning of the year, will go up in logic as local officials and forensic scientists re-categorize causes of winter deaths attributed at the time to pneumonia or influenza.
The Santa Clara County medical examiner, which includes Silicon Valley, announced Tuesday evening that three people who died at home on February 6 and 17 and March 6 had, after autopsies, tested positive for the coronavirus.
Since several weeks (in the order of three to four) generally separate the contamination from death, this can be traced back to the beginning or the middle of January. The first official coronavirus deaths in the United States were earlier than February 26.
“If this is indeed the case, the models of the epidemic in the United States will have to be adjusted to take into account this early departure date,” said Stanford professor of medicine Jay Bhattacharya. “The models will have to scale up the number of current cases,” he told AFP.
The three Californian cases, whose whereabouts are unknown, apparently had not traveled to China, said Sara Cody, county public health official, at the Washington Post.
Arrival in December?
It is unknown why it took so long to test these bodies, but local officials pointed to the Centers for Disease Prevention and Control (CDC), which until late February insisted on limiting screening tests only people returning from China with symptoms.
It was not until February that the testing policy was relaxed, and around mid-March that the gates were actually opened.
The veil is gradually being lifted, a posteriori, on the arrival of the coronavirus in America.
The epidemic began in December in Wuhan, but it was not until January 31 that the United States closed its border with China and began to impose quarantines.
Throughout the month of January, top CDC officials assured that the risk remained “low” for the Americans. They were then persuaded that the contagions were limited to the cases returning from China, which they believed capable of containing with targeted surveillance measures. But this method allowed contagious but asymptomatic people to escape.
Other indications of an early arrival of the coronavirus come from genetic analyzes.
Two teams of geneticists in New York established that the virus had started to spread in the metropolis of the East coast from mid-February, coming from Europe – whereas the first confirmed local case had only been announced on the 1st March, in a woman returned from Iran.
They know this because the virus, by replicating itself, mutates, like all viruses. Analysis of the genomes of viruses recovered in March from New Yorkers made it possible to reconstruct a coronavirus family tree, since mutations occur at regular intervals.
California officials expect to find more old Covid-19 cases. Santa Clara County official Jeff Smith said recently that Sars-Cov-2 may have arrived on its shores in December.
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