CD19 and influenza: This may differ between centers and be deferred (other than inactivated influenza vaccine) to commence at 12 months if there is potential for delayed immune reconstitution or negative impact of therapy, indicated by therapies received including anti‐cluster of differentiation 20 (CD20) mAb <6 months ago or blood parameters including CD4+ T‐cell count <200/μL and cluster of differentiation 19 (CD19)+ B‐cell count <20/μL.24, 31, 32, 33, 34, 35