The shingles vaccine

Question: If you've had shingles, should you get the vaccine to protect yourself from getting it again?

Answer: Shingles is caused by the reactivation of varicella-zoster virus — the virus that causes chickenpox — that has lingered, often for decades, in a dormant state in the nervous system. The most common symptom is a bad rash on the torso or face that can be quite painful. In about 10% to 20% of cases, the rash is followed by postherpetic neuralgia — pain emanating from an affected nerve, which can be excruciating and last for many months. Shingles can also affect the eyes, causing significant pain and, in the most serious cases, loss of vision. It's safe to say that those who have had shingles don't want to have it again — especially if they've had postherpetic neuralgia or eye problems as a result.

But is a second case of shingles something we need to worry about, or does the first one give immunity against a repeat episode? And if it doesn't, does that mean that people who have had shingles should get the shingles vaccine?

When the FDA approved the shingles vaccine (sold under the brand name Zostavax) in 2006, the agency posted a question-and-answer piece — which is still on its Web site — that says an episode of shingles boosts immunity to the varicella-zoster virus, so people who have had shingles are unlikely to have a second case. The same piece notes that the effectiveness of Zostavax in preventing repeat episodes of shingles "has not been demonstrated in clinical studies." And the FDA-approved prescribing information (the package insert) for the vaccine is silent on the subject of whether people should be vaccinated after they have already had shingles.

In 2008, the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices (ACIP) recommended people ages 60 and over get the shingles vaccine. The lengthy statement on the recommendation says some studies suggest the chance of a recurrence of shingles is about the same as getting shingles in the first place. The ACIP recommendation is more permissive ("Persons with a reported history of zoster can be vaccinated") than directive, but it is at odds with the advice from the FDA.

About a million Americans get shingles every year, and the numbers have been increasing, so the ambiguity about whether to get vaccinated after an episode affects a lot of people. What makes it an even tougher choice for many is that the vaccine, which costs about $200, is covered by Medicare Part D plans, but not Part B, meaning there may be some out-of-pocket expense.

There's not much doubt now that shingles can recur, so if an initial case gives some immunity against a subsequent one, it's not absolute. In the large, industry-sponsored Shingles Prevention Study that was the basis for FDA approval of the vaccine, there were two confirmed repeat cases among the 642 people in the placebo arm of the study who got shingles. If that were the only data to go by, the 0.3% risk of a second episode could be dismissed as small, and vaccination for protection against it as unnecessary.

But there are other data. One study that's often cited was conducted in Olmsted County, Minn., where the Mayo Clinic is located. Dr. Barbara Yawn, director of research at the Olmsted Medical Center, and her colleagues have reported that over a period of a little over seven years, 95 of the 1,669 adults in the county diagnosed with shingles had a recurrence later on. That works out to a risk of 5.6%, which is comparable to the risk of getting an initial case of shingles for people ages 60 and older.

If the Olmsted County study accurately reflects the risk of getting shingles a second time, then vaccination to prevent it seems worthwhile.

One sticking point might be that 26 of the recurrent cases were confirmed with lab tests, so it's possible that the recurrence risk is less than 5.6%, which, depending on how much less, could weaken the case for vaccination after having had shingles. Another complication is that no study has been done that shows the vaccine prevents second episodes. It's a reasonable assumption that it would, but the study hasn't been done to show it.

So there's no easy answer to whether people who have had shingles should get the shingles vaccine. Some pretty good data suggest that the risk of recurrence is quite high and, particularly if you've had a bad case, getting the vaccination would seem to be a prudent precaution. But it's also possible to make a case for the evidence not being all that solid.