Paul G. Auwaerter, MD


May 18, 2011

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Hi. This is Paul Auwaerter here for Medscape Infectious Diseases. I would like to talk today about the zoster vaccine, which has been approved since 2006 and has just recently been in receipt of a new indication, lowering the age to 50.

The vaccine has been available since 2006. From a large registration trial,[1] it looked as though people who received the vaccine over the age of 60 had more than a 60% reduction in the incidence of shingles, as well as postherpetic neuralgia.

Of interest, this vaccine only helps prevent the reactivation of the varicella zoster virus and is not really primary prevention. In fact, over the years it has been of interest that this vaccine is probably more important in giving a boost to cell-mediated immunity, rather than antibody production as its main contribution in preventing the re-emergence of this virus.

Some newer information has come to light. A recent retrospective cohort series that was published in the Journal of the American Medical Association,[2] has confirmed that this vaccine is indeed effective, achieving about a 55% reduction in shingles for all ages. Of course, it's not uncommon for shingles to lessen as people age. As people get into their 70s and 80s, perhaps the vaccine is not as efficacious, but this reduction in efficacy is by no means unique to the zoster vaccine. A large study looking at the safety of this vaccine on the basis of the initial registration was published in 2010.[3] No difference between placebo and vaccine were seen in terms of side effects. Both groups were associated with a 1.4% risk for serious adverse effects. The data, at least, do not suggest that safety is at all an issue.

The vaccine has had other challenges, mainly because initially, it had to be frozen. In addition, different insurance programs did not treat it as a vaccine, but rather as a drug. Now the US Food and Drug Administration (FDA) has approved lowering the age indication to 50 for the vaccine, on the basis of postmarketing information and data in over 22,000 patients who were followed for an average of 1.5 years.[4] The risk for shingles in the 50-59 year age group is about 5 per 1000 -- not a trivial number. From the submitted data, it looked like there was a 70% reduction in incidence of zoster, which is even more than that seen in populations of 60 and older.

Whether insurance companies will pay for this vaccine and back this kind of immunization practice is not clear, but it does seem as though a rationale exists for giving the shingles vaccine, even starting at the age of 50, with no increased risks. What has always been uncertain is whether there is a need for boosting and whether boosting provides additional efficacy, but this will only be known after considerable further study.

A last issue is coadministration of zoster with, for example, another commonly administered vaccine in older age groups -- the pneumococcal polysaccharide vaccine. In 2009, the prescribing information for the zoster vaccine was changed to suggest that the pneumococcal polysaccharide and zoster vaccines should not be administered simultaneously, based on studies that showed decreased antibody levels to the zoster vaccine. However, antibody levels are not the right surrogate. Cell-mediated immunity is probably more important. A recent study published in Vaccine by Tseng and colleagues[5] suggested no difference between patients who received the 2 vaccines concurrently or separately. At least in real-world practice, it looked like this was probably not an issue. Although the labeling may remain intact, it is probably not something about which clinicians should be too concerned.

I do a little bit of primary care, and for any patient who has had shingles, the vaccine is an easy sell. For people who are not as familiar with shingles, it is sometimes more difficult, especially if there are out-of-pocket costs. However, it does seem that the immunization is even better at age 50. Whether it is more durable remains unknown.

In closing, the zoster vaccine seems to be efficacious at the ages of 50 and older and now has FDA approval for this age range. Newer data have come to light that perhaps it is not necessary to avoid the coadministration of the shingles vaccine and pneumococcal polysaccharide vaccine. Of course, immunization in any age group is always a challenge, so 1 less barrier is indeed perhaps a welcome respite. Thanks very much for listening.