New autopsies show US virus spread began in January

The earliest US death attributed to the coronavirus was previously thought to be on February 26. Photo: Reuters

Two people who died in California in early and mid February have been confirmed through autopsies as coronavirus cases - weeks before the first reported Covid-19 fatality in the United States.



The deaths, on February 6 and February 17, push back the timeline for the entry of the virus on US soil, experts said.



Given what we know about how long it takes for the virus to kill people, the disease began to spread in the US sometime between early and mid January.



And the fact that it took astute health officials to carry out post mortem examinations on these selected cases in turn means that the overall death toll of 45,000 is likely well below the real number.



"Models of epidemic spread in the US will have to be adjusted to account for an earlier start date," Jay Bhattacharya, a professor of medicine at Stanford University said.



"This in turn should mean that the models will predict a larger number of current cases in the US now than they are currently predicting. How large an effect this will have on epidemic forecasting remains to be seen."



The earliest death attributed to the coronavirus was previously thought to be on February 26 in Washington state - a man in his 30s who returned from the disease's epicentre in Wuhan and reported himself to authorities after experiencing symptoms.



Sara Cody, the public health officer of Santa Clara County where the new autopsies were performed, told The Washington Post it was not yet known how the two people were infected, with officials unaware of any history of overseas travel.



This further reinforces that the virus was already circulating in the community at a time that the Centers for Disease Control and Prevention (CDC) was continually assuring the public that the threat posed by Covid-19 was "low."



Another person who died in Santa Clara County on March 6 also had the disease caused by the coronavirus, the medical examiner-coroner said in a statement.



"These three individuals died at home during a time when very limited testing was available only through the CDC," the coroner said.



"Testing criteria set by the CDC at the time restricted testing to only individuals with a known travel history and who sought medical care for specific symptoms."



The coroner said they expected to identify more coronavirus-related fatalities in Santa Clara.



A study this week led by Bhattacharya at Stanford indicated that the novel coronavirus was likely far more widespread than official figures suggest.



Blood samples taken from 3,300 volunteers in Santa Clara County showed the true number of Covid-19 cases was at least 50 times higher than the number of confirmed infections in the county.



Santa Clara was among the first areas in the US to tell residents to stay at home to contain the spread of the virus, ordering a shutdown from March 17.



On the other side of the country, researchers determined that the virus was spreading in New York City in February, and the predominant strain came from Europe.



This finding tied in with a spate of mysterious pneumonia cases that the city's physicians were treating before large scale testing began.



Viruses mutate over time and there are enough genetic changes for scientists to trace back their ancestry, much like a person's DNA can be traced back to their parents and grandparents.



California officials expect to find other old cases of Covid-19.



Santa Clara County official Jeff Smith said recently that the virus may have arrived on US shores as early as December - days after China first identified the pathogen. (AFP)