That doesn’t mean they haven’t already had it or it was such a mild case it didn’t register enough with assympomatic (same reason lots of people had to have multiple tests done). It’s why you do an anti-body study. It’s how they figured out the swine flu was only .02% death rate rather than the 1-5% originally thought.
I doubt it. This virus doesn’t spread so easily. You literally have to come in contact with an infected person’s saliva.