Safety and reactogenicity of the recombinant zoster vaccine after allogeneic hematopoietic cell transplantation.

Allogeneic hematopoietic cell transplantation (HCT) recipients are at increased risk for varicella zoster virus (VZV) reactivation and associated complications. A nonlive adjuvanted recombinant zoster vaccine (RZV) has been developed to prevent herpes zoster (HZ), but there are no recommendations for use in this population. In this single-center prospective observational cohort study, we assessed the safety and reactogenicity of RZV, as well as incidence of graft-versus-host disease (GVHD) and confirmed cases of HZ after vaccination. Between December of 2018 and June of 2020, patients aged ≥18 years received 2 doses of RZV between 9 and 24 months after HCT, with the doses separated by ≥8 weeks. One hundred and fifty-eight patients (mean age, 55 years; 42% women) received ≥1 dose (total vaccinated cohort), and 150 patients (95%) received 2 doses (modified total vaccinated cohort). Solicited reactions occurred in 92.1% of patients (grade 3, 32.5%), owing mostly to injection site pain, which occurred in 86% (grade 3, 16%). The cumulative incidence of GVHD in the peri-vaccination period was no different than in historical controls (adjusted incidence rate ratio, 1.05; 95% confidence interval, 0.8-1.38). There were 4 cases of HZ in the total vaccinated cohort (2.5%) and 3 cases in the modified total vaccinated cohort (28.3/1000 person-years). Among recipients of allogeneic HCT, RZV was safe, tolerable, and did not increase rates of GVHD. Future clinical trials are needed to determine the immunogenicity and efficacy of RZV in this population.