I doubt we'll ever know the exact dates, but I suspect there was a gap of weeks, probably more than a month, between Wuhan officials being told they had a problem and the Chinese government notifying WHO (12/31/19) that they had a problem. And even then travel from Wuhan and other major Hubei Province cities was not restricted until January 23rd. That 6-9 week (or whatever it was) delay allowed coronavirus to become a nationwide epidemic and to become a worldwide pandemic. It also proved to corporations worldwide that they could not place all their production eggs in Chinese baskets. I don't know how the percentages will play out in the next 1-5 years, but that 6-9 week delay will have lasting effects on the economies of China and the nations to which some manufacturing is shifted.
IMO, China is compounding that shift by threatening to cut off US pharmaceuticals. The US may be their target for now, but countries not currently targeted will be paying attention. This threat will come back on China like a storm of boomerangs.