Friday, January 14, 2011

The Shingles (Herpes Zoster) Vaccine Really Works But Many Older Folks Don’t Receive It - They Should

Herpes zoster (or shingles) is caused by the same virus that causes chicken pox. Zoster increases in incidence with advancing age. It is estimated that over 1 million Americans get shingles annually with the resulting acute discomfort and often chronic pain thereafter. A vaccine was introduced by Merck in 2006; the initial studies of 38,546 patients indicated that it reduced the incidence by about 50% and for those who still got shingles, the severity was lessened substantially. But acceptance of the vaccine has been slow. It seems that this is due to a combination of lack of knowledge that it is available and is effective; failure of physicians to inform their patients; and a fairly high cost of about $200, often not covered by insurance.

A new study was reported in JAMA January 12, 2011. Kaiser Permanente, Southern California and Centers for Disease Control and Prevention investigators evaluated 75,761 Kaiser members who had no underlying immunological disorder and who had been vaccinated between January, 2007 and December 2009. These were compared to a control group of 227,283 age matched members who had not been vaccinated.

Among the unvaccinated individuals, this study showed that, as anticipated, shingles incidence goes up with age from - 60-64 years of age (9.7 infections per 1000 person years) to over age 80 (17.3 per 1000 person years).

Vaccination reduced the frequency by about 50% from a total of 13.0 per 1000 person years to 6.4 per 1000 person years. This halving of incidence was found at all age intervals, indicating that the vaccine works as well in the very elderly as in “younger” individuals. The incidence of zoster was steady over time. For example, at one year, slightly more that 1% of the unvaccinated individuals had developed zoster compared to less that 0.05% in the vaccinated group; at two years the numbers were about 2 ½ % and 1%, respectively. During the time of patient follow-up, this can be stated as one case of herpes zoster was prevented with each 71 vaccinated. However, since the follow up was only about 1 ½ years for most individuals and since it is estimated that beginning at age 60 a person has a 20% lifetime risk of zoster, it is my presumption that it actually takes many fewer individuals vaccinated to prevent one episode of zoster over the rest of one’s life.

Not part of this study, the original Merck investigation demonstrated that many older people do not respond well to the vaccine with increases in antibody production. This finding is consistent with many others that those over 60 years of age respond much less well than do those who are younger. This raises the question as to whether it would be useful to measure antibody production after vaccination to determine who has and who has not responded well. Perhaps those who do not should get a second vaccination. This is an important issue for all vaccines in older people. The same occurs with influenza vaccine which is why, this year, the dose for older people was doubled. But perhaps there are other approaches as well to improving the response rates for those at increased risk in their older years who respond less well to vaccines.

The study makes clear that this vaccine is effective, including for those over 80 years of age where the incidence is the highest. Given the implications of herpes zoster in immediate and longer term suffering and the attendant costs, I believe this is a vaccine that essentially everyone over the age of 60 (other than immunocompromised individuals) should receive. Insurance should pay for it just as with the influenza vaccine.

Even if paid for out of pocket, it is worth it. Patients need to ask for it and doctors need to encourage it.

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Praise for Dr Schimpff

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