It's nothing to do with them catching it, it's about them spreading it.
The usually bandied figure is 80% immunity to stop the pandemic.
Without the teenagers vaccinated, that's never going to get hit.
Wait until winter hits and the cases spike, then it's suddenly going to become "necessary", but if they'd made that hard decision 3 months ago this would already be over.
How can they know that figure (80%) without knowing % of people with natural immunity? We can guess but there hasn't been much of an effort made to track this.
> The usually bandied figure is 80% immunity to stop the pandemic.
That was pre-Delta. The higher the R0, the more mitigation we need to do. The question is what gets RE below zero.
At this point, with Delta's R0 and the vaccine's effectiveness, it looks like mere vaccination without masks is going to be insufficient in large groups (e.g. at a giant concert, a big play). But, since all the precautions have a multiplier, that's fine. It means we can keep doing those things as long as we take precautions while we do it and not assume vaccine = ignore COVID.
The usually bandied figure is 80% immunity to stop the pandemic.
Without the teenagers vaccinated, that's never going to get hit.
Wait until winter hits and the cases spike, then it's suddenly going to become "necessary", but if they'd made that hard decision 3 months ago this would already be over.