A highly efficacious herpes zoster subunit vaccine (HZ/su) may also lessen the incidence of HZ-complications in immunocompetent older adults, according to a study published in Vaccine.
Herpes zoster results from latent varicella zoster virus (VZV) reactivation in sensory ganglia years after primary infection. Postherpetic neuralgia (PHN), the most common HZ complication, is persistent chronic neuropathic pain after resolution of HZ rash. PHN development is seen in >30% of adults aged ≥50 years. Incidence, duration, and severity of PHN and other HZ-complications increase with age, including HZ vasculitis; disseminated HZ; ophthalmic, visceral, or neurologic disease; and stroke.
Two phase 3 clinical trials, ZOE-50 (n=15,411; ClinicalTrials.gov Identifier: NCT01165177) and ZOE-70 (n=13,900; ClinicalTrials.gov Identifier: NCT01165229), showed HZ/su to be highly efficacious in preventing HZ and PHN in older adults. Data from both clinical trials were analyzed to evaluate the efficacy of HZ/su in preventing HZ-associated complications, hospitalizations, and death.
ZOE-50 included 15,411 adults aged ≥50 years; ZOE-70 included 13,900 adults aged ≥70 years. Throughout the ZOE-50 study period (mean follow-up, 3.9±0.7 years), 263 patients had a confirmed HZ episode: 9 in the HZ/su group and 254 in the placebo group. Throughout the ZOE-70 study period (mean follow-up, 3.7±0.8 years), 246 subjects had confirmed HZ episodes: 23 in the HZ/su group and 223 in the placebo group.
HZ/su efficacy against HZ-related mortality or hospitalization was 100% (P =.0636). ZOE-50 had no reported hospitalizations or deaths related to an HZ episode. ZOE-70 had no reported hospitalizations or deaths in the HZ/su group, but 5 HZ-related hospitalizations were reported in the placebo group: neurologic disease (n=2), disseminated HZ (n=1), neurologic and ophthalmic disease (n=1), and reaction to codeine for HZ pain relief (n=1). The number of hospitalizations in ZOE-50 compared with ZOE-70 was not statistically significant.
HZ/su reduced the risk for HZ-related complications other than PHN by 93.7% (P =.0003) in patients aged ≥50 years and 91.6% (P =.0035) in patients age ≥70 years. In the combined population of ZOE-50/ZOE-70, only 1 HZ-related complication (ophthalmic disease) was reported in 32 HZ/su recipients confirmed with HZ (3.1%). At least 1 HZ-related complication other than PHN was reported in 16/477 (3.4%) of placebo recipients confirmed with HZ. Other reported complications in the placebo group were ophthalmic disease (n=7), disseminated disease (n=6), neurologic disease (n=3), and vasculitis (n=1).
HZ/su also reduced the risk for HZ-related PHN. In the combined HZ-confirmed population of ZOE-50/ZOE-70, PHN and other complications were reported in 5/32 (15.6%) HZ/su patients and 58/477 (12.2%) placebo patients. HZ/su reduced HZ-related complications, including PHN, by 91.3% (P <.0001) in patients aged ≥50 years and by 88.6% (P <.0001) in patients aged ≥70 years.
Although some analyses of this study were done post hoc, results were consistent with the overall HZ/su efficacy against HZ: 97.2% in adults aged ≥50 years (ZOE-50) and 91.3% in adults aged ≥70 years (ZOE-50/ZOE-70). Based on these new results, the study investigators concluded that “vaccination with two doses of HZ/su substantially reduces the overall risk of HZ-associated complications among adults ≥50 years.”
Disclosure: This study was funded by GlaxoSmithKline Biologics.
Kovac M, Lal H, Cunningham AL, et al; ZOE-50/70 Study Group. Complications of herpes zoster in immunocompetent older adults: incidence in vaccine and placebo groups in two large phase 3 trials. Vaccine. 2018;36(12):1537-1541.