Conference Coverage

High efficacy, no safety signals for herpes zoster vaccine post-HSCT



Postherpetic neuralgia (PHN) prevention efficacy – a secondary endpoint – was 89.3% for those receiving the vaccine (HZ/su); the incidence of PHN was 0.5% in the HZ/su study arm, compared with 4.9% for those who received placebo (95% CI, 22.5-99.8). The study also tracked other HZ complications as a secondary endpoint, finding efficacy of 77.8% (95% CI, 19.1–95.0). “The vaccine was highly efficacious in preventing all the secondary outcomes,” said Dr. de la Serna of the Hospital Universitario 12 de Octubre, Madrid.

The randomized, observer-blind phase 3 trial was conducted in 28 countries.Adults who received autologous HSCT were randomized 1:1 to receive HZ/su (n = 922) or placebo (n = 924) within 50-70 days of their transplant. Patients were excluded if they were expected to receive more than 6 months of anti–varicella zoster prophylaxis posttransplant, Dr. de la Serna said.

Participants received the first dose of HZ/su at the first study visit, and the second dose 30-60 days later. Patients were seen 1 month after the last vaccine dose, and then again at months 13 and 25, with telephone follow-up between the later visits. All participants were followed for at least 1 year, Dr. de la Serna said.

Episodes of HZ were confirmed by polymerase chain reaction assay, or, when samples were lacking or indeterminate, by agreement of at least three members of an ascertainment committee.

Of the two components of the HZ/su vaccine, glycoprotein E triggers both humoral immunity and activity of varicella zoster–specific CD4+ T cells; the adjuvant system – dubbed ASO1 – boosts immune response. The vaccine was approved by the Food and Drug Administration in October 2017 for use in adults aged 50 years and older.

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