Ok, my first attempt at getting a digital vaccination certificate was successful. I gave the pharmacist my WHO immunization card (*) and my CDC card and walked out with my two QR codes.
I was surprised that I actually got two certificates, one for each shot with different QR codes. But the Covid Warn app happily accepted both. Now I need to find a place where I can actually use it. Will they want to scan both QR code’s, or just the one for shot #2?
You can search for pharmacies in Germany that issue the digital certificate using this website:
https://www.mein-apothekenmanager.de
(*) I had my shots added to my yellow vaccine passport at my local county health department.