As the health professional who sees more patients than any other, it is important that pharmacists understand the value to the patient, public health and the pharmacy of promoting the benefits of prevention through the use of zoster vaccine in individuals 50 years of age and older.
By Rosemarie Patodia, BScPhm, CGP
The measure of the burden of illness of a disease includes consideration of both direct (e.g., hospitalization, physician care, drug expenditures) and indirect (lost production due to injury, illness or death) costs.
Many clinical studies have concluded that herpes zoster is a widespread disease associated with a heavy social and economic burden. Higher direct costs are associated with increasing age, comorbidities, and drug treatment, while being employed predicts higher indirect costs. About 20-35% of the population in developed countries will acquire HZ at some time in their life. In individuals who live to the age of 85 years who have not been vaccinated (virtually all at this point and time), the risk of acquiring herpes zoster is about 50%. There are complications in 13-40% of cases which include painful postherpetic neuralgia (clinically significant pain persisting for more than 90 days after the onset of rash) in 8-27% of cases.
The risk of complications increases with age, and is 4 times higher in individuals older than 70 years than in those under 60 years. Up to 3% of individuals with herpes zoster require hospitalization. Disease prevention is the best way to reduce the burden of illness of a disease. This is often achievable in a high percentage of cases through immunization.
When considering recommendation of an immunization program, policy makers take into account the burden of illness of the disease to be prevented, the vaccine efficacy and safety, and the cost-effectiveness of vaccination. The Shingles Prevention Study was a landmark randomized placebo-controlled trial which included 38,456 individuals over the age of 60 years given either herpes zoster vaccine or placebo.
After a median follow-up of 3.1 years, incidence of herpes zoster, incidence of postherpetic neuralgia, and burden of illness were all significantly reduced (p< 0.001) in the herpes zoster vaccination group versus the placebo group, by 51.3%, 66.5% and 61.1% respectively. After the positive results of the Shingles Prevention Study were published, another large study, involving 22,439 adults between the ages of 50-59 years was conducted in a similar manner. Results showed that zoster vaccine significantly reduced incidence of herpes zoster by 70% over a 1.3 year period versus placebo.
Safety of the vaccine in the two studies cited was similar in the two treatment groups with the exception of mild injection site reactions which were significantly more prevalent in the herpes zoster vaccination groups. Headache was also more prevalent with zoster vaccine in the 50-59 year old age group. The zoster vaccine was shown to be cost-effective in 10 out of 11 studies assessed in a systematic pharmacoeconomic review. The vaccine cost-effectiveness increased with age and in those patients who were employed.
Based on the criteria of burden of illness reduction, vaccine efficacy and safety, and cost-effectiveness in the 50 years and older age group, zoster vaccine is a public health initiative that pharmacists should be advocating for at both a personal and public health level.