COVID vaccination before transplant

My husband is over 65, so he was able to get his Covid vaccination in early 2021 (Jan-Feb). At the time, he had just been listed for a liver transplant due to Primary Biliary Cirrhosis/Cholangitis. In April 2021, he received his new liver and is now on various anti-rejection immune suppression medications. My question is whether there is any information being collected on transplant recipients who were vaccinated BEFORE transplant; that is, does their immunity to Covid survive the transplant and the transplant medications? Everything I read about transplant patients and vaccines pertains to people with pre-Covid transplants who are now wondering if they derive any benefit from the vaccine. So the people I'm talking about would be a pretty small group: people vaccinated in early '21 and transplanted since then. There hasn't been much time to follow them, but perhaps more of them will be coming along, as transplant teams seem pretty busy lately. (I mean, while I'm on the topic: do pre-transplant vaccines for, e.g., shingles, flu, whooping cough, tetanus still protect you after transplant?)