It was in late December, while scrolling through his Twitter feed, that Gao Fei first noticed chatter about a possible virus outbreak in Wuhan. Mr Gao, who had grown up near Wuhan, regularly used virtual private network software to hop over the “Great Firewall”, as China’s internet censorship regime is more popularly known, to access banned sites such as Twitter. While government officials and state media were saying very little about the virus, he was determined to learn more. As doubts about the true size of the outbreak grew through January, Mr Gao, 33, decided to rush home from southern Guangdong province where he was working as a welder. He arrived in his home village, about 120km from Wuhan, on January 21, just a day after the Chinese government finally broke its silence about the epidemic and confirmed the virus was spreading human-to-human. The Chinese government had formally notified the World Health Organization on January 3 that a “severe pneumonia of unknown etiology” — science speak for a mysterious new respiratory disease — had been discovered in Wuhan, capital of Hubei province with a population of 11m. But for the first three weeks of January, Chinese officials said there were only a few dozen confirmed cases and downplayed the risk of human transmission....