Early spread of 2019-nCoV was far greater than reported say University researchers

Published: Wednesday, 05 February 2020 08:45

Infectious disease researchers at The University of Texas at Austin and other institutions in Hong Kong, mainland China and France have concluded that there is a high probability that the 2019-nCoV coronavirus spread beyond Wuhan and other quarantined cities before Chinese officials were able to put a quarantine in place.

At least 128 cities in China outside of the quarantine zone, including cities with no reported cases to date, had a greater than even risk of exposure, according to a paper currently in press with Emerging Infectious Diseases, a journal of the US Centers for Disease Control and Prevention.

Based on comprehensive travel data from location-based services and modeling of the disease done at UT Austin's Texas Advanced Computing Center, 128 cities in China had a 50 percent chance or greater risk that someone exposed to the virus traveled there before the quarantine began. The team also estimated there were 11,213 cases of the coronavirus in Wuhan by the time of the quarantine - a rate 10 times higher than the reported cases.

"This risk assessment identified several cities throughout China likely to be harboring yet undetected cases of [Wuhan coronavirus] and suggests that early 2020 ground and rail travel seeded cases far beyond the Wuhan region quarantine," write the authors.

As of February 4th, officials have confirmed 425 fatalities from the virus, all but two in mainland China, and more than 20,000 confirmed cases spread across the world.

The paper shows there is a 99 percent chance that at least one patient carrying the virus traveled to the cities of Beijing, Guangzhou, Shenzhen and Shanghai by the time the quarantine was put in place for the city of Wuhan on January 23rd. The quarantine has since expanded to include cities with populations totaling 60 million people. Beijing reported its first fatality from the virus on January 27th.

The team estimated new cases of the virus doubled roughly every week, and on average, that every infected person transmitted the disease to approximately two other people.

The model also takes into account the reported cases of the disease outside of China to estimate the rates of epidemic growth.

Based on the team's estimates, there are at least 128 cities and as many as 186 cities in China that had at least a 50 percent chance of an infected visitor from Wuhan arriving sometime in the three weeks before the quarantine was enacted. Several cities reporting no cases had a 99 percent probability that an infected person visited. Those cities - each with a population of more than 2 million people - include Fushun, Laibin and Chuxiong.