Cost-Effectiveness of a Vaccine To Prevent Herpes Zoster (Shingles) in Older Adults

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The summary below is from the full report titled "Cost-Effectiveness of a Vaccine To Prevent Herpes Zoster and Postherpetic Neuralgia in Older Adults." It is in the 5 September 2006 issue of Annals of Internal Medicine (volume 145, pages 317-325). The authors are J. Hornberger and K. Robertus.

What is the problem and what is known about it so far?

Herpes zoster (also called shingles) is a condition in which painful blisters develop on the skin along the path of a nerve. Shingles results from infection with the varicella zoster virus (the same virus that causes chickenpox). After chickenpox, the virus remains inactive in nerves. Years later, shingles develops when the virus becomes active during periods of illness or stress. People usually recover from shingles in a few weeks, but up to half of people develop lasting pain in the affected area. This pain is known as postherpetic neuralgia. Shingles becomes more common with older age. A 2005 study showed that the varicella zoster virus vaccine reduces the occurrence of shingles when given to people 60 years of age or older. We do not know whether the costs of the vaccine are worth the potential benefits.

Why did the researchers do this particular study?

To determine which factors influence the cost-effectiveness of varicella vaccine for older adults. This information might be helpful in pricing the vaccine appropriately.

Who was studied?

Rather than studying actual patients, the researchers used computers to simulate what would happen to a virtual group of people older than 60 years of age.

How was the study done?

Using published information, the researchers estimated what might happen if people older than 60 years of age did (or did not) get the varicella zoster vaccine. They put this information into a computer model. Their analysis included potential vaccine costs from $50 to $500. The computer calculated how much it would cost for each year of life saved by avoiding shingles and postherpetic neuralgia. The calculations accounted for the quality of life, as well as for the years of life saved. The computer model also looked at conditions that would bring cost-effectiveness into the range that Americans typically consider to be acceptable (less than $100,000 per quality-adjusted year of life saved).

What did the researchers find?

Giving varicella zoster vaccine to people older than 60 years of age increases the quality-adjusted life span by a small amount (0.6 day). However, vaccination would have reasonable cost-effectiveness if the vaccine cost was less than $200, people were vaccinated before 70 years of age, and the vaccine remained effective for more than 30 years.

What were the limitations of the study?

This study was a computer simulation to help with decision making, so we cannot be sure what the results would be with actual people. In addition, the computer model predicts what might happen on average in a large population of people. These results do not mean that persons who get vaccinated will live 0.6 day longer than those who do not get vaccinated.

What are the implications of the study?

Many uncertainties influence whether the cost-effectiveness of herpes zoster vaccination will be within a range that Americans typically view as reasonable for health care interventions.