Vaccination stops you getting a serious case of Covid. It also reduces the possibility of transmission but it doesn't eliminate it entirely. So when 1 in 300 have the virus you have to be careful especially when half the population haven't been vaccinated. The lower the prevalence, and the higher proportion of people that are vaccinated, the less restrictions that are required and you can say to vaccinated people that you can mix.
If we look in the UK in isolation, 31m have had 1 vaccine dose, 5m have had 2 doses. We are well on our way to vaccinating the population. However, we are an island on the globe.
We will know this is ending when we outrun the virus globally. At the moment I don't know the extent to which the virus is evolving. If I don't know that, then all I can do is play the numbers game. If the global pandemic comes under control through vaccination and natural immunity, then we will reach a point when a 2nd variant vaccine will enable us to exit the cycle. The best scenario is that we don't even need a variant vaccine because the variants don't or can't evolve far enough.