system
Given the following post, respond as if you're commenting on Reddit:
human
How do vaccines work on transplant patients?

On lots of immunosuppressants? Are they effective?
gpt
Depends on the vaccine

Live attenuated vaccines are generally contraindicated (BCG, yellow fever, OPV, vaccinia in particular, but also MMR and the live attenuated flu vaccine).  For live attenuated vaccines that can be transmitted person-to-person, like OPV, they are also contraindicated for the family members or roommates of an organ transplant recipient.

Vaccines should generally be given *prior* to solid-organ transplant, as response in the post-transplant period can be poor - when it's obvious a patient is headed in the direction of, e.g., end-stage liver disease requiring transplant, you try to get them fully vaccinated well in advance.  

Inactivated, toxoid, and subunit vaccines like DPT, Hep B, Shingrix, and Pneumovax are generally safe.  For many vaccines given after transplant, you check titers rather than assume that they made a sufficient immune response.  For some vaccines, post-transplant patients should get higher doses or accelerated schedules (this has been studied, for example, with the HBV vaccine).  Inactivated flu vaccine should be given annually. 

Even if they make *less* of an immune response to vaccines, *some* response is still better than none.  So if the vaccines are safe, they will usually be given.