Originally Posted by
FlyingfromDC
don't have to rush now to get a booster shot just for a 2-hour transit through Frankfurt.
You may need it for more than that, though. If anywhere in your destination country requires a Covid certificate, AFAIK same rules will apply, because there was an agreement on the Union level about the 270-day validity of vaccination certificates. So, if your destination requires certs to get into places, you'll either have to get tested, or get that booster shot.