Breakthrough Covid-19 infections in vaccinated recipients of allogeneic stem cell transplantation

[摘要] Allogeneic hematopoietic stem cell transplant (HSCT) recipients areat high risk of developing severe and/or lethal forms of Coronavirusdisease 19 (Covid-19), the entity described 3 years ago and related tothe emergence in China of a novel coronavirus referred to as severeacute respiratory syndrome coronavirus 2 (SARS-CoV-2). Whilehope has arisen a year ago from the promising results of messengerRNA (mRNA) vaccines studies, showing high protection rates and afavorable safety profile, some concerns remain regarding the efficacyof vaccination in HSCT recipients, as humoral response might bealtered in this setting because of concomitant immunosuppressivemedications, and delay or alteration in B-cell reconstitution. We andothers previously identified that patients in the 3–12 months postHSCT developed significantly lower antibody titers after vaccinationcompared with patients in the > 12 months post-HSCT group andhealthy controls [1, 2], making the first year after HSCT a period ofcritical susceptibility to breakthrough Covid-19 infections.