According to a new study by researchers at the University of Hong Kong, the number of infected in mid-February in the Asian giant could have been up to four times higher than the official if a more extensive accounting method had been applied.
On February 20, Chinese authorities reported 55,000 positive cases of COVID-19 across the country, mainly concentrated in Hubei province and its capital, Wuhan. However, according to the study published in the scientific journal The Lancet, the actual number could have quadrupled if a revised definition adopted earlier that month had been applied.
Between January 15 and March 3, the Chinese National Health Commission issued up to seven different guidelines for the diagnosis and treatment of COVID-19, modifying the classification system for infected people as understanding of the disease progressed. In this sense, the authors assure that the different definitions made a great difference in the number of cases counted.
According to the study’s estimates, each of the first four changes ―from version 1 to version 5―, increased the proportion of cases detected and accounted for between 2.8 and 7.1 times. In the fifth version of the guidelines, published on February 5, China modified the classification to also include those diagnosed clinically (with an image of the lung, for example) rather than requiring confirmation of both clinical symptoms and laboratory tests. The inclusion of these cases led to a sudden jump in the number of cases, although authorities reversed their decision few days later.
In this sense, if the fifth version of the case definition had been applied throughout the outbreak with sufficient evidence, the authors estimate that by February 20, 2020 there would be some 232,000 confirmed cases in China compared to 55,508 cases reported.
Link to the paper: https://doi.org/10.1016/S2468-2667(20)30089-X
Editorial Disclaimer: information published during the 2020 COVID-19 pandemic may be updated frequently to reflect the dynamic nature of current understanding.