A Vaccine to Prevent Shingles

Zostavax, a vaccine to prevent shingles, has recently been approved by the FDA and reviewed by The Medical Letter.

Shingles (also called herpes zoster) is a very painful illness involving blisters that occur in a stripe-like pattern on one side of the body.  Shingles can only happen in people who have had chicken pox.  The virus that causes chicken pox, varicella zoster virus (VZV), stays in the in sensory nerve cells of the infected person forever.  As decades pass after the initial illness, our natural immunity slowly fades, and enables VZV to reactivate, causing shingles.  Typically the blisters in shingles resolve after a couple of weeks.  In some people, however, the pain persists for months or even years.  This persistent pain is called postherpetic neuralgia (PHN).  PHN can be debilitating and happens most frequently in older patients.  It occurs to about a third of patients with shingles over 60.  Usually the immune response to an episode of shingles is quite strong, and it is unusual for patients with normal immune systems to have shingles again.

The Singles Prevention Study randomized over 38 thousand adults 60 years of age and older who have had chicken pox to receive either Zostavax or placebo.  They were followed for about three years.  Shingles occurred in 315 vaccine recipients and 642 placebo recipients.  PHN developed in 27 vaccine recipients and in 80 placebo recipients.  That means that 59 people have to be vaccinated to prevent one case of shingles over three years, and 364 people have to be vaccinated to prevent one case of PHN.

The vaccine is indicated for adults 60 or older who have had chicken pox and are not immunocompromised.  I would not recommend it to anyone who has already had shingles.  The biggest unknown factor is the duration of effectiveness, which would determine how frequently it would need to be readministered.

The CDC has not yet made a formal recommendation about Zostavax, but they are expected to do so in the next few months, so I’ll be keeping an eye on their vaccine-preventable diseases page.  In the meantime, shingles is treatable with antiviral medication, and the treatment works best if started within three days of onset of the rash.  So if you get a painful rash, don’t delay seeing your doctor.

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