@Christen you're right! If I remember right, the Chinese authorities knew about it already in November 2019. I remember traveling in Thailand and Cambodia from Dec 26th until mid January 2020. We saw lots and lots of Chinese tourist groups there. We stayed in a big hotel in Siem Reap, Cambodia. We were among a handful of Westerners, and there were at least a couple of hundred Chinese tourists there. Or more. We met them at the breakfast buffet. They were traveling freely in January when we knew nothing about covid. But the Chinese authorities knew.