December 1 – The first lab-confirmed patient of novel coronavirus, as measured by a Lancet study published by Chinese doctors, begins to feel sick. This first patient had no link to the Huanan wholesale seafood market – the presumed origin of the COVID-19 outbreak – nor did they have a connection to subsequent cases. However, the same study finds that 66% of the first 41 admitted hospitalizations through to January 2 had some level of exposure to the market.

December 10 – Wei Guixian starts to feel ill. Wei is one of the first known cases at the Huanan wholesale seafood market. She is hospitalized at Wuhan Union Hospital on December 16.

December 27 – A Guangzhou-based genomics company sequences most of the virus; the results from this first sample and subsequent samples from other infected patients in Wuhan bear a striking resemblence to the SARS coronavirus, a fact noted by many of the technicians who examine the data.