Brandon told this big lie after it was known that the virus did not prevent infection or transmission. It was all to scare people into compliance and to persecute Trump supporters. Evil.
If memory serves me correct, at the time he made this statement, it was very much public knowledge that the people who were vaccinated was still getting omicron and getting sick from it.
I have yet to find any evidence at this vaccine, ever stops the transmission or sickness from the virus. Just like you still had to wear a mask if you were vaccinated until enough, other people were vaccinated before the mandates were lifted because you could still have the unvaccinated Covid.
If it worked like the vaccine, the second you got vaccinated you should be able to take the mask off and not get it or spread it.