Oh, and wouldn't you know... EpiTwitter is reminding people that while we know that efficacy for you getting sick is high, we still don't know if vaccinated people are unable to infect someone else. The 2nd half of the equation.
So you get exposed, but you are vaccinated, so your body gets to work, and while you are technically infected, you will have no symptoms. The live virus that entered your system, can you spread it before it's eliminated? Is it neutralized? Primate studies so far have said, transmission is still possible. Other non-COVID vaccines, transmission is still possible; there is a track record.
So for
@Chi84's question about why they still need to wear a mask... the answer is we don't know yet if you could still be Typhoid Mary, even if you're vaccinated.
Apparently, there are other vaccines still in development that do show prevention of transmission in primate tests. (Novavax and Janssen)