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.

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 are limited. This prospective single-center cohort study (April 2014 to March 2018) included adult allo-HSCT recipients referred to a dedicated vaccinology consultation and vaccinated with the pediatric combined diphtheria, tetanus, acellular pertussis, hepatitis B virus, inactivated poliovirus, and Haemophilus influenzae type b (DTaP(±HB)-IPV-Hib) vaccine (3 doses 1 month apart, booster dose 1 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. A total of 106 patients were vaccinated at a median (interquartile range) time of 12.4 (10 to 18.4) months post-transplant. At 5.3 (4.8 to 6.6) and 23.1 (21.1 to 25.1) months after vaccine initiation, high and sustained rates of protective antibody titers were achieved for tetanus (97.8% [95% confidence interval (95% CI), 92.4% to 99.7%], n = 91/93 and 100% [95% CI, 92% to 100%], n = 44/44), diphtheria (94.6% [95% CI, 87.9% to 98.2%], n = 88/93 and 90.9% [95% CI, 78.3% to 97.5%], n = 40/44), Hib (96.6% [95% CI, 90.4% to 99.3%], n = 85/88 and 93% [95% CI, 80.9% to 98.5%], n = 40/43), and hepatitis B (83.5% [95% CI, 73.5% to 90.9%], n = 66/79 and 81.1% [95% CI, 64.8% to 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 3 doses but not in the long term (24 months). Six (5.7%) patients experienced mild side effects. 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.