You can transmit with asymptomatic infection, symptomatic infection and without infection. That doesn't change regardless of the percent of the population vaccinated. I'm sorry but that makes no sense. It serves to do nothing other than convince people that the unvaccinated are a problem.I'm not saying with a certainty that it would, but I'm saying that's the only time it might. But to somewhat answer, you can transmit without infection, so theoretically if everyone were vaccinated the R would drop below 1 and the virus would burn out. I'm not saying that would absolutely happen, but that is how a vaccine that wasn't 100% effective could do it.