You do realise they threw darts at a board to come up with that number. It's what public health do on
Friday nights when they get on the beers. Because they are so faceless who's to say that I'm wrong.
Over a year ago they knew the answer, I watched an Interview back then listing the vaccination rate and the number they said then was 80-90%. The magic number was 60% actual immunity rate in the population required to curb and significantly slow community transmission. Then factor that by Vaccine efficacy of say mean 75% which is where the 80% required vaccinated population comes from. The issue was that getting above 75% would be hard due to issues like people who cant take the vaccine and anti vaxxers.