> The very first signs of human-to-human transmission in the epidemic were on Jan 14th, as some family members of the initially-identified cluster began to fall ill.

If you're referring to the case covered by the article published in The Lancet[1], those patients were admitted to hospital between Jan 10 and Jan 15.

Yet, prior to that date there were already reports the virus spread between humans.

[1] https://www.thelancet.com/journals/lancet/article/PIIS0140-6...