It's interesting to view the timeline.
Ill people Wash State a person whom visited Wuhan, then another in Chicago, a single person in so cal and 2 more recent Wuhan visitors, all asked to voluntarily quarantine themselves. 195 State Dept employees non test +. In Chicago a single person to person infection from spouse whom visited China (the 2nd person mentioned above. All this was in January. Bringing 195 St Dept Employees home definitely had governments attention back then. Things accelerated after and China visitors were suspect while European Strains got a foothold on the East Coast. In this early mess Cruise ships many Chinese and God only knows how many people streamed into the country from abroad.
Sure begs the question how it escaped attention. It's a Novel Virus. Flares had been launched for weeks before it gained National attention. Now, it will take years to truly get over the impacts.