Vaccine response after pneumococcal vaccination in allogeneic hematopoietic stem cell transplant recipients.

Current guidelines for vaccination in allogeneic hematopoietic stem cell transplant (HCT) recipients recommend initiation of pneumococcal vaccination series three to six months post-HCT, with most data supporting initiation at six months due to a more robust immune response. This single-center, retrospective, observational chart review aimed to evaluate the impact of initiating the pneumococcal vaccine series at three months post-HCT compared to six months post-HCT. The primary endpoints were defined as a percentage of patients with a serologic response of >1 and >1.3 µg/mL for over 50% of the defined serotypes. Outcomes showed no difference in immunologic response between the two groups.