What they found was that while the virus had spread rapidly within the Huanan Seafood Wholesale Market in Wuhan, there had also been two major population expansions on December 8 and January 6.

According to the study, which was published on the institute’s website on Thursday, analysis suggested that the coronavirus was introduced from outside the market.

“The crowded market then boosted SARS-CoV-2 circulation and spread it to the whole city in early December 2019,” it said.

The research went on to say that based on the genome data it was possible that the virus began spreading from person to person in early December or even as early as late November.

“The study concerning whether Huanan market is the only birthplace of SARS-CoV-2 is of great significance for finding its source and determining the intermediate host, so as to control the epidemic and prevent it from spreading again,” the research team said.

The scientists said also that although China’s National Centre for Disease Control and Prevention issued a Level 2 emergency warning about the new coronavirus on January 6, the information was not widely shared.

“If the warning had attracted more attention, the number of cases both nationally and globally in mid-to-late January would have been reduced,” they said.

Meanwhile, Xiang Nijuan, a researcher at the Chinese Centre for Disease Control and Prevention, said in an interview with state broadcaster CCTV on Saturday that people infected with the new coronavirus were contagious two days before they showed any symptoms.

Therefore anyone who had been in close contact with someone within 48 hours of them being confirmed as infected should put themselves in isolation for 14 days, he said.