Joint consensus statement on the vaccination of adult and paediatric haematopoietic stem cell transplant recipients: Prepared on behalf of the British society of blood and marrow transplantation and cellular therapy (BSBMTCT), the Children's cancer and Leukaemia Group (CCLG), and British Infection Association (BIA)

Long‐term survivorship care after CAR‐T cell therapy

“…Complete reimmunization may be particularly important for patients with more profound deficits in humoral immunity, such as recipients of BCMA-directed CAR-T cell therapy or those with a history of HCT who have not undergone post-transplant vaccinations. 79,80,88 The optimal time to initiate immunizations after CAR-T cell therapy is uncertain, but it has been recommended to commence non-live vaccines >6 months after CAR-T cell therapy and live vaccines >1 year when fully immune reconstituted (i.e., CD4 count >200 Â 10 6 /L, B cells repopulated, and no immunosuppression). 18,73 However, preliminary data suggest that pneumococcal vaccinations do not elicit humoral responses if administered within 3-6 months of CAR-T cell infusion but may do so when given beyond the 1-year mark.…”

“…Despite this, a significant proportion of CAR‐T cell recipients have low or absent antibody titers against specific pathogens such as streptococcus pneumoniae, haemophilus influenzae, pertussis, and hepatitis B, 80,85,86 providing a rationale for implementing complete or at least partial revaccination series following CAR‐T cell therapy. Complete reimmunization may be particularly important for patients with more profound deficits in humoral immunity, such as recipients of BCMA‐directed CAR‐T cell therapy or those with a history of HCT who have not undergone post‐transplant vaccinations 79,80,88 . The optimal time to initiate immunizations after CAR‐T cell therapy is uncertain, but it has been recommended to commence non‐live vaccines >6 months after CAR‐T cell therapy and live vaccines >1 year when fully immune reconstituted (i.e., CD4 count >200 × 10 6 /L, B cells repopulated, and no immunosuppression) 18,73 .…”

Vaccinations in children with hematologic malignancies and those receiving hematopoietic stem cell transplants or cellular therapies

“…Moreover, patients with prior immunity to MMR are likely to lose protection post‐HSCT, underlining the importance of posttransplant vaccination 79 . HSCT recipients are therefore treated as “never vaccinated” and comprehensive revaccination is advised 12,80 . In accordance with immune ontogeny, conjugated vaccines and protein subunit vaccines are administered earlier, as polysaccharide vaccines are less effective in early IR and live viral vaccines risk inducing disease if given prior to adequate IR 81,82 .…”

“…Between 2000 and 2009, CDC guidelines advised post‐HSCT vaccination begin at 12 months and MMR (the sole live vaccine advised) be delayed to 24 months and only administered to patients without GVHD and off immunosuppression 83 . More recent published consensus guidelines 12,14,80,84,85 recommend starting recipient vaccination with nonreplicating vaccines at 3–6 months post‐HSCT (using minimal recommended dosing intervals if feasible), though delay is advised in the setting of moderate to severe chronic GVHD and/or continuing significant immunosuppression (such as ongoing chemotherapy or recent T‐ or B‐cell depleting therapy) 80 . Of note, Haynes et al.…”

“…Guidelines recommend live vaccines (MMR and VZV) still be administered 24 months post‐HSCT 86 . Suggested minimum criteria of IR post‐HSCT are included in Table 2 13,76,80,86 …”