huge vaccine hesitancy
Not actually so with the Coronavirus vaccine -- the number of people who say "I don't want to get the vaccine" is only around 11.3%, with young people being the ones most likely to say that. This is around the UK's numbers, I believe.
The real bottleneck now is consistent supply, and there's actualy a shortage because demand is far outpacing supply -- there's a few things I know about it, e.g.: