I suspect the fact that we're in the middle of a pandemic has something to do with this, though. In particular, the demand is such that we urgently need hundre

I suspect the fact that we're in the middle of a pandemic has something to do with this, though. In particular, the demand is such that we urgently need hundreds of millions (or billions?) of doses. That takes a lot of effort to roll out. Most vaccines probably don't see use at that scale and speed. An HIV vaccine, for example, would probably initially only go out to communities with higher risk.