Pneumonia Vaccine in Bone Marrow Transplant Recipients: Usefulness of Donor Vaccination

This is a randomized controlled trial designed to assess the immunogenicity of the new pneumococcal conjugate vaccine in a cohort of allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients. This will be done by using an approach of pre-transplant donor immunization with post-transplant recipient immunization. Response will be compared with the standard 23-valent polysaccharide vaccine. It is hypothesized that the conjugate vaccine will provide an enhanced response in this group of immunosuppressed individuals who respond poorly to standard polysaccharide vaccines.

Specific objectives of this study are:

• To determine the antibody response to both vaccines via a measurement of total antibody response and by the opsonophagocytic assay. This assay has the advantage of assessing if patient antibody responses represent truly functional antibodies that display opsonic activity against pneumococcus and is likely better correlated with protective efficacy.
• To determine any acute adverse reactions of the conjugate vaccine in this population. Results of this trial will help lay the foundation for the development of a rationale and optimal pneumococcal vaccination strategy that would prevent significant morbidity in this patient population.

We hypothesize that pneumococcal conjugate vaccine, due to its T-cell dependent response will have greater immunogenicity and protective effect in an allo-HSCT population by using a donor immunization strategy.