Estimates Vary Widely for Number of Wuhan COVID-19 Cases in January

Lacking many diagnostic test results from the first major outbreak, researchers have been left to scour other sources for clues about what happened in the early days of the pandemic.

Written byChris Baraniuk
| 5 min read
wuhan china coronavirus pandemic covid-19 estimate modeling cases

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ABOVE: Wuhan, China, January 24, 2020
© ISTOCK.COM, JULIEN VIRY

Five months since COVID-19 exploded in Wuhan, researchers still don’t know exactly how many people caught the disease in the city during those crucial early days of the outbreak. At the heart of this problem is the fact that testing in the city of 11 million people was very limited in those early days of the outbreak. By January 23, the first day of the city’s lockdown, just 495 cases had been officially confirmed.

As one researcher based in Hong Kong puts it, Chinese authorities were clearly aware that they had a much bigger problem on their hands than that number suggested.

“They decided to build the hospitals, they sent doctors to Wuhan,” says Daihai He, a mathematical epidemiologist at Hong Kong Polytechnic University, referring to two hospitals with capacity for more than 2,500 people that were constructed in early February ...

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  • chris baraniuk

    Chris Baraniuk is a freelance science journalist based in Northern Ireland who contributes to The Scientist. He has covered biological and medical science for a range of publications, including the BBC, the BMJ, and Mosaic. He also writes about nature, climate change, and technology. His background in the humanities has long proved invaluable in his quest to bring science stories to people from all walks of life.

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