Safety and immunogenicity of the live attenuated varicella vaccine following T replete or T cell depleted related and unrelated allogeneic hematopoietic cell transplantation (alloHCT)

摘要

There are limited studies assessing the live attenuated varicella vaccine following alloHCT. Due to the morbidity of varicella acquired after childhood, we immunized and retrospectively analyzed the safety and immunogenicity of this vaccine in 46 VZV seronegative patients <20 years old at HCT who achieved a CD4 cell count ≥200/ul, were off immunosuppression, and responded to ≥1 post HCT vaccines. Two vaccinated patients lacking follow-up titers were excluded from analysis. Stem cells were derived from an HLA-matched sibling (n=18) or an alternative (HLA MM related or unrelated) donor (n=26). Median time to vaccination was 4 years. Sixty-four percent of patients seroconverted following one immunization. There was no significant difference in response between recipients of a matched related or alternative donor graft (p=0.2) or between those given a TCD or T-replete alternative donor graft (p=0.27). Three of 44 patients developed a self-limited varicella-like rash within 2.5 weeks of immunization. With a median follow-up of 29.1 (range: 6.9-167.1 ) months, there were no subsequent cases of varicella-like rashes. No patient developed shingles. This study suggests that this vaccine is safe and immunogenic when given according to pre-set clinical and immunologic milestones, warranting larger prospective studies in patients ≥24 months following HCT as outlined in current post HCT vaccine guidelines.