Once all the kids are vaccinated (and BTW even the WHO is taking a cautious approach on this given that it's unclear whether young children are at more risk from Covid or the shots), what's the plan for preventing variants from developing in the developed world? In animal reservoirs? In the large numbers of vaccinated people who still wind up hosting (usually minor and asymptomatic) infections?

If vaccine escape happens because the UK had its schools open then I find it very difficult to believe "we vaccinate everyone at once and the virus just goes away" was ever a realistic prospect in the first place.