Tracing 'patient zero': why America's first coronavirus death may for ever go unmarked

The US is nearing the bleak milestone of 100,000 confirmed coronavirus deaths. But the actual death toll will probably have hit that figure days before the official tallies reflect it. And despite scientists’ best efforts, that date may for ever go unmarked.

Coronavirus was probably spreading through the US before the Trump administration restricted travel from China, before the US had a reliable supply of diagnostic tests, and before the disease caused by the virus was even named. Models of the Covid-19 outbreak estimate that the virus was making its way through America’s major cities, undetected, weeks before a California woman in early February became the first American known to have died of related causes.

Researchers are now doing detective work, revisiting autopsies from early this year and studying how the virus has subtly evolved to try to trace when Covid-19 may have first