Herpes Zoster Vaccine Safe and Immunogenic in HSCT Recipients

Among patients with hematologic malignancies, live herpes zoster vaccination demonstrated immunogenicity and safety when administered 2 years post-hematopoietic stem cell transplantation (HSCT), according to study results published in BMC Infectious Diseases.

A team of investigators conducted a clinical study to determine the optimal vaccination timing, and the temporal immunogenicity and safety of a live herpes zoster vaccine among patients who were either 2 to 5 years or more than 5 years post-HSCT.

Investigators used a glycoprotein enzyme-linked immunosorbent assay (gpELISA) and an interferon-g enzyme-linked immunospot (ELISPOT) assay to measure humoral and cellular immunogenicity. They also measured vaccine-related adverse events.

A total of 56 patients with hematologic malignancies and 30 healthy volunteers (control group) were included in the analysis. Among patients with hematologic malignancies, 41 survived either autologous or allogeneic HSCT (2-5 years post-HSCT, n=26; >5 years post-HSCT, n=15). Further, 15 patients with hematologic malignancies who had undergone cytotoxic chemotherapy and survived without relapse for at least 6 months were included in an additional control group.

At baseline, the gpELISA geometric titers were similar among patients in the 2- to 5-year post-HSCT group, the chemotherapy control group, and healthy volunteer control group; values were significantly lower in the HSCT greater than 5-year group (P =.041). Compared with baseline results, gpELISA immune responses at 6 weeks post-vaccination increased significantly for all groups.

Geometric mean fold rises in humoral immune responses for both HSCT groups were comparable to those of the healthy volunteer group but significantly higher than those of the chemotherapy group. Baseline gpELISA geometric mean titers were higher among patients with a history of shingles; however, geometric mean fold rises were unaffected by shingles status.

The geometric mean fold rises seen in ELISPOT were highest among participants in the 2- to 5- year post-HSCT group and lowest in the chemotherapy group.  Patients with a history of shingles had a generally higher baseline geometric mean concentration of interferon-g-secreting peripheral blood mononuclear cells, compared with patients without a history of shingles; however, geometric mean fold rises were unaffected by shingles status.

There were no reported cases of varicella zoster virus reactivation up to 6 weeks post-vaccination in any of the study groups. The most common adverse events reported were at injection site and included local pain, redness, edema, and itching. In addition, all adverse events were grade 1 (mild) and occurred within 7 days of vaccination.

Study limitations included fewer patients that were qualified for the ELISPOT assay compared with the gpELISA assay due to blood sample sufficiency, fewer patients in the HSCT greater than 5 years group, and time of monitoring vaccine adverse events.

“In practical terms, we expect to continue using live [varicella zoster virus] vaccines (at least for a few years); therefore, the immunogenicity and safety data presented herein will be useful in clinical practice,” the researchers concluded.

Reference

Chun JY, Kim K, Lee MK, et al. Immunogenicity and safety of a live herpes zoster vaccine in hematopoietic stem cell transplant recipients. BMC Infect Dis. 2021;21(1):117. doi:10.1186/s12879-021-05806-4