The number of people infected during the first wave of Coronavirus in mainland China may have been four times the official figures, according to a new survey.
Some 55,000 cases had been reported as of February 20th, but as many as 232,000 may have been infected, according to research by academics at Hong Kong University's school of publish health, published in the Lancet.
Researchers said the true number would have been higher if the definition of a Covid - 19 case that was used later had been used earlier.
Between January 15 and March 3, China's national health commission issued seven different definitions of Covid-19, and the study found the changes had a "substantial effect" on how many infections were detected.
Analysing data from the World Health Organisation, the researchers concluded "If the fifth version of the case definition had been applied throughout the outbreak with sufficient testing capacity, we estimated that by Feb 20, 2020 there would have been 232,000 confirmed cases in China as opposed to the 55,508 confirmed cases reported"
Some 55,000 cases had been reported as of February 20th, but as many as 232,000 may have been infected, according to research by academics at Hong Kong University's school of publish health, published in the Lancet.
Researchers said the true number would have been higher if the definition of a Covid - 19 case that was used later had been used earlier.
Between January 15 and March 3, China's national health commission issued seven different definitions of Covid-19, and the study found the changes had a "substantial effect" on how many infections were detected.
Analysing data from the World Health Organisation, the researchers concluded "If the fifth version of the case definition had been applied throughout the outbreak with sufficient testing capacity, we estimated that by Feb 20, 2020 there would have been 232,000 confirmed cases in China as opposed to the 55,508 confirmed cases reported"