Ever since one of the astronauts got sick on one of the Gemini missions the astronauts have undergone quarantines for a period before going up into space.
And still Ken Mattingly was pulled from Apollo 13 3 days before takeoff because of a potential exposure to measles.
In the live video, most of the technicians and even Musk are wearing masks, most of them staying at some distance though. I doubt they were all quarantined for the last 2 weeks.