# Antibody response to tetanus, diphtheria, poliomyelitis, hepatitis B, and H. influenzae b vaccines in allogeneic hematopoietic stem cell transplant adult recipients: A multicenter trial

## TL;DR

This study shows that adult allogeneic stem cell transplant recipients can develop strong antibody responses to five vaccines when given in the first year post-transplant.

## Contribution

The study provides empirical evidence on the immunogenicity of multiple vaccines in post-transplant adults, a population with limited prior data.

## Key findings

- Seroprotection rates after three vaccine doses were high for tetanus, diphtheria, poliomyelitis, and H. influenzae b.
- A booster dose at month 12 improved hepatitis B seroprotection from 78.3% to 84.1%.
- Vaccination was safe with only benign adverse effects reported.

## Abstract

National and international guidelines recommend vaccinating hematopoietic stem cell transplant (HSCT) recipients, although relatively few studies have evaluated immunogenicity in adults. We therefore aimed to assess the immune response in adult allogeneic HSCT recipients vaccinated against tetanus, diphtheria, poliomyelitis, hepatitis B, and H. influenzae b.

We conducted a multicenter prospective study. HSCT recipients were included at least 6 months post-transplantation (maximum: 24 months) if blood CD19 + lymphocytes were ≥0.1 G/L and plasma immunoglobulin ≥ 4g/L, and if no immunosuppressive therapy was applied. They received the hexavalent pediatric combination vaccine for tetanus, diphtheria, poliomyelitis, hepatitis B, and H. influenzae b (and pertussis) at months 0, 1, 2, and 12 (in addition to other recommended vaccines). Plasma antibodies against the five valences were quantified at inclusion and 1 month after the third and fourth doses.

We included 104 HSCT recipients (median age: 58 years [IQR:48–64]). Study vaccination was initiated a median of 11 months [IQR:9–14] after transplantation. Median [IQR] values for CD19 and plasma gammaglobulin at inclusion were 0.3 [0.2–0.6] G/L and 7.9 [6.4–11.1] g/L, respectively. Seroprotection after three doses and after the M12 booster was achieved for 97.2% and 97.5% of participants for tetanus, 100% and 97.5% for diphtheria, 96.6% and 92.7% for poliomyelitis, 78.3% and 84.1% for hepatitis B, and 94.6% and 95.0% for H. influenzae b. Adverse effects were benign.

Vaccination against these five infections initiated during the first year post-allograft is immunogenic and should be performed in every recipient not undergoing immunosuppressive therapy.

ClinicalTrials.gov NCT03402776