The median duration of discomfort and pain was shorter in the vaccinated group than in the placebo group, at 21 days and 24 days, respectively, investigators say.
The zoster vaccine, Oka/Merck VZV, has been proven to reduce morbidity from herpes zoster and postherpetic neuralgia in older individuals, according to the results of a study published in The New England Journal of Medicine.
The incidence and severity of both herpes zoster and postherpetic neuralgia increase with age, because of a decrease in immunity to the varicella zoster virus (VZV), investigators said.
More than 95% of the individuals completed the study, with a median of 3.12 years of surveillance for herpes zoster, investigators said.
There were a total of 957 confirmed herpes zoster cases, with 315 from individuals who received the vaccine and 642 cases from those who received the placebo.
Additionally, there were 107 cases of postherpetic neuralgia, with 27 cases from those who received the vaccine and 80 among those who received the placebo.
The median duration of discomfort and pain was shorter in the vaccine group than in the placebo group, at 21 days and 24 days, respectively. Similarly, the severity of illness, determined by the mean herpes-zoster severity-of-illness score, was lower in the vaccine group at 141.2 compared with the placebo group at 180.5.
Additionally, the effect of the zoster vaccine was greater among older individuals in terms of severity of illness.
The number of individuals who had 1 or more adverse events in the vaccine group was greater than the number of individuals in the placebo group.
It was estimated that the zoster vaccine reduced the burden of illness related to herpes zoster by approximately 61.1% overall, approximately 66.5% for the incidence of postherpetic neuralgia, and approximately 51.3% for the incidence of herpes zoster.
Furthermore, the use of antiviral medication among individuals with cases of herpes zoster was similar in both groups at approximately 87.3% in the vaccine group and approximately 85.7% in the placebo group. The rate of treatment initiated within the first 72 hours after the onset of a rash was also similar in both groups at approximately 64.1% in the vaccine group and approximately 65.9% in the placebo group.
Additionally, the use of various medications used to treat the pain was similar in both groups. However, the use and average quantity of opioids was higher in the placebo group than in the vaccine group.
The double-blind, placebo-controlled, randomized study enrolled 38,546 individuals who were aged 60 years and older between November 1998 and September 2001. The follow-up was completed in April 2004.
Investigators diagnosed herpes zoster according to clinical and laboratory criteria, and the discomfort and pain from herpes zoster were measured repeatedly for 6 months.
The study was conducted at 22 sites where individuals received either the VZV vaccine or a placebo.
Additionally, the primary endpoint was burden of illness from herpes zoster, a measure affected by the incidence, severity, and duration of discomfort and pain. The secondary endpoint was the incidence of postherpetic neuralgia.
Oxman MN, Levin MJ, Johnson GR, Schmader KE, et al. Shingles prevention study group. A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults. N Engl J Med. 2005;352(22):2271-84. doi:10.1056/NEJMoa051016