Coronavirus study points to vast number of cases under the radar in China
- Researchers in Hong Kong find that Covid-19 definitions make big differences to the pandemic’s bigger picture
- Mainland China might have had four times as many infections as official total if broader criteria used, team says
In a study published in the medical journal The Lancet on Tuesday, the researchers said China might have had 232,000 confirmed cases – rather than the official total of about 55,000 – by February 20 if a revised definition adopted earlier in the month had been applied throughout.
“We estimated that there were at least 232,000 infections in the first epidemic wave of Covid-19 in mainland China,” they said, referring to the disease caused by the coronavirus.
“The true number of infections could still be higher than that currently estimated considering the possibility of under-detection of some infections, particularly those that were mild and asymptomatic, even under the broadest case definitions.”
The researchers – led by Peng Wu from the University of Hong Kong’s school of public health – looked at the various classification systems used by the government after the epidemic erupted in the central Chinese city of Wuhan in late December.
China has published seven editions of diagnosis and treatment guidelines, changing the classification system as understanding of the disease developed.