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
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