"Instead of the virus being able to hop from person to person to person, potentially mutating and becoming more virulent and drug resistant along the way, now we know that the vaccines work well enough that the virus stops with every vaccinated person.
A vaccinated person gets exposed to the virus. The virus does not infect them. The virus cannot then use that person to go anywhere else. It cannot use a vaccinated person as a host to get more people.
That means the vaccines will get us to the end of this. If we just go fast enough to get the whole population vaccinated. It`s huge news."
https://www.msnbc.com/transcripts/transcript-rachel-maddow-show-3-29-21-n1262442