(TibetanReview.net, Apr23’20) – China might have had 232,000 confirmed Covid-19 cases – rather than the official total of about 55,000 – by Feb 20 if a revised definition adopted earlier in the month had been applied throughout, a study published in the medical journal The Lancet Apr 21 by researchers at the University of Hong Kong was cited as saying.
“We estimated that there were at least 232,000 infections in the first epidemic wave of Covid-19 in mainland China,” the researchers were quoted as saying, referring to the disease caused by the novel coronavirus.
Besides, “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 Dec 2019, reported scmp.com Apr 23
Noting that different definitions made a big difference to the number of cases, the Hong Kong team has said in the report, which was co-authored by Peng’s HKU colleagues epidemiologist Benjamin Cowling and medical faculty dean Gabriel Leung: “We estimated that when the case definitions were changed from version 1 to 2, version 2 to 4, and version 4 to 5, the proportion of infections being identified as Covid-19 cases was increased by 7.1 times from version 1 to 2, 2.8 times from version 2 to 4, and 4.2 times from version 4 to 5.”
The report was said to note that in the fifth version of the guidelines released on Feb 5, China modified its classification of confirmed cases to include diagnosis by symptoms only rather than requiring confirmation by both clinical symptoms and laboratory tests. The inclusion of these cases led to a sudden jump in confirmed cases before the authorities reversed the decision more than a week later on Feb 17.
The HKU team was reported to have found that if the fifth definition were used throughout the epidemic, the total number of confirmed cases could have reached 232,000 by Feb 20, instead of the 55,508 confirmed cases throughout the country.