Efficacy and safety of revaccination against tetanus, diphtheria, Haemophilus influenzae type b and hepatitis B virus in a prospective cohort of adult recipients of allogeneic hematopoietic stem cell transplantation.

Abstract Background Data on immunogenicity and safety of the recommended revaccination schedule against diphtheria, tetanus, poliomyelitis, pertussis, Haemophilus influenzae type b (Hib) and hepatitis B in adult allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients is limited. Methods Prospective single-center cohort study (April 2014-March 2018) of adult allo-HSCT recipients referred to a dedicated vaccinology consultation and vaccinated with the pediatric combined DTaP(±HB)-IPV-Hib vaccine (three doses one month apart, booster dose one year later). The proportion of responders to tetanus, diphtheria, Hib and hepatitis B vaccine and geometric mean concentrations (GMCs) of antibodies were assessed before and up to 24 months after vaccination. Results A total of 106 patients were vaccinated at a median (IQR) time of 12.4 months (10-18.4) post-transplant. At 5.3 (4.8-6.6) and 23.1 months (21.1-25.1) after vaccine initiation, high and sustained rates of protective antibody titers were achieved for tetanus (97.8% [95% confidence interval {95%CI}, 92.4-99.7]; n=91/93 and 100% [95%CI, 92-100]; n=44/44), diphtheria (94.6% [95%CI, 87.9-98.2]; n=88/93 and 90.9% [95%CI, 78.3-97.5]; n=40/44), Hib (96.6% [95%CI, 90.4-99.3]; n=85/88 and 93% [95%CI, 80.9-98.5]; n=40/43) and hepatitis B (83.5% [95%CI, 73.5-90.9]; n=66/79 and 81.1% [95%CI, 64.8-92]; n=30/37). Underlying disease, stem cell source, chronic graft-versus-host-disease, and extracorporeal photopheresis differentially influenced GMCs of tetanus, diphtheria, and hepatitis B antibodies after three doses but not in the long-term (24 months). Six (5.7%) patients experienced mild side effects. Conclusions The pediatric DTaP(±HB)-IPV-Hib vaccine was safe and effective in eliciting a sustained protective humoral response in adult allo-HSCT recipients. Hepatitis B revaccination might be optimized by using higher antigen doses.