Britain - which is of course highly vaccinated - is seeing recent small (so far) problems with spikes as well [1], due to the Delta (India B.1.617.2) variant now spreading there. There doesn't seem to be much consensus as to what a high-vaccination (and, in theory, high herd immunity) location like Britain might expect against that variant. The US will find out pretty soon how the mRNA vaccines hold up against it, as I imagine it'll blanket the US in the coming months.

[1] https://www.theguardian.com/world/2021/may/31/scientists-cal...