Disease study in Nature verifies China's COVID-19 numbers

A research paper that has developed a new model to track the spread of COVID-19 via mobile phone geo-location tracking published online in the journal Nature on Wednesday offered support for the reliability of China's official case counts.

In developing the model, researchers used phone location data of over 11.4 million people who left or passed through Wuhan between Jan 1 and 24 -- a period covering the run-up to the Chinese Lunar New Year and the annual chunyun mass migration in China. They moved to 296 cities in 31 provinces and regions throughout the Chinese mainland.

The population-flow data, which was provided by a major national wireless telecommunications carrier, was then linked to COVID-19 infection counts provided by the Chinese Center for Disease Control and Prevention, by location and time at the prefecture level.

The article showed the distribution of population outflow from Wuhan accurately predicts the relative frequency and geographic distribution of COVID-19 infections through Feb 19 across all of China.

The analysis also corroborates data released by the Chinese CDC through Feb 19, because a totally independent source of information – the telecom carrier – is very well correlated with official COVID-19 case counts.

Nicholas A. Christakis, a co-author and social scientist and physician at Yale University, tweeted on Wednesday: "Incidentally, this result sheds light on accuracy of Chinese COVID-19 reporting, because a totally different source of info (telco mobility) obtained from different source predicts case counts so well, in keeping with epidemiological expectations (at least until Feb 19)".