看来华春莹说1月3日起通知美国是真的

https://www.cdc.gov/coronavirus/2019-nCoV/summary.html#risk-assessment

CDC established a COVID-19 Incident Management System on January 7, 2020. On January 21, CDC activated its Emergency Operations Center to better provide ongoing support to the COVID-19 response.

以后是不是应该经常去CDC网页上瞅瞅，没准能更早得到信息.

Dr. Krutika Kuppalli on twitter说12月底就知道武汉发现新病毒了，一个月前左右说的，翻不到记录了。