But won’t vaccines nearly being done for all adults by then make a big change from last year?
Yes, my comparison with last year was on the 'shape of the graph' rather than the 'specific nature of the cases within the graph'.
This wave has been built, very substantially, on cases in younger age groups. Of those age groups, only the vaccination status of 18+ will have changed by September, and then only just - 18 yo DD, in a region known for being somewhat ahead of national rollout, will get her second vaccine towards the end of August.
The age groups brought together in their hundreds / thousands by return to school (in far greater numbers, and with a far greater concentration of the unvaccinated, compared with summertime mixing) will still be unvaccinated in September, and it is from that group I would imagine that the surge in cases will reappear. It may well grow faster, if unseen, because of the lack of self-isolation.
The impact on higher age groups - and therefore on hospitalisations and deaths - is somewhat unknown. The oldest groups could be caught between waning immunity from initial vaccination but pre-booster by schools returning at the very start of Septembe.