Again. Read my post. You still fail to grasp the basic concept. Throughout history, the most simple minds have failed to grasp basic concepts. I grasp the fact you continue that intrinsic fact in 2020.
Really? Let's walk through the time line shall we?
Infection date: Dec. Let's make it easy and say 12/31/19.
Incubation period: two weeks. During which they would not show symptoms. After which, symptoms will appear.
She flies back to NYC fro China, and then starts infecting people. Say 1/2/20.
By 1/15 she would start showing symptoms.
By 1/23, the first wave of people she infected would start showing symptoms.
By 1/30, the people she first infected would have infected others, and they would start showing symptoms.
Math to today would be an exponential infection factor of at least 4.
Where are those cases? She would have been Patient Zero for a small outbreak.