On boosters, don't forget we (in the West) came under a lot of external pressure from WHO and the scientific body, including Oxford, NOT to boost our vulnerable population before the rest of the world has had even one dose. As always, all these decisions are very finely balanced health, economic, diplomatic, issues.
Personally I think we should have opened up vaccination to 12-16's earlier, but again, the jury was out at the time it was up for debate. Some went for it early, some countries only vaccinated vulnerable youngsters, Germany decided against, and then changed their mind, much like us, but then got going earlier. China (and Chile) vaccinates 3 year olds and potentially soon to go younger. Not sure how that would go down here.