Heads up.

The sole US supplier of YF vaccine is only shipping 5 dose vials. Likely it will be this way until March or even later. The problem is YF is only good for one hour after being reconstituted.

What does this mean? Most, if not all, travel clinics that run out of YF are booking YF "clinics" to give shots in to folks in groups of five. You may not be able to get a last minute YF vaccination if one is required for your destination.