If you are 50 or older and haven't been vaccinated against varicella zoster virus (VZV), which causes both chicken pox and shingles, you should strongly consider it, says Anne Louise Oaklander, MD, PhD, FAAN, associate professor of neurology at Harvard Medical School.

"More than 95 percent of Americans have been exposed to VZV and harbor the latent virus," says Maria Nagel, MD, FAAN, associate professor of neurology at the University of Colorado School of Medicine.

The latent virus hides in the nerve cells and can reemerge as shingles, a painful rash usually on the chest, back, or face. The rash typically disappears within a few days, but the effects can linger as postherpetic neuralgia, a condition where the virus leaves scars in the skin, nerves, nerve roots, and spinal cord, resulting in sensitivity and pain on the skin, Dr. Oaklander says. "[The virus] can also cause stroke, encephalitis, blindness, and problems in any nerves it infects."

More Effective Vaccine

Until last year, the only vaccine for shingles was the zoster vaccine live (Zostavax), a vaccine containing a live but weakened form of the virus.

In October 2017, the US Food and Drug Administration (FDA) approved zoster vaccine recombinant, adjuvanted (Shingrix), based on two studies that demonstrated it was more effective than Zostavax. The Shingrix vaccine contains inactivated (nonlive) protein from VZV, along with an adjuvant (known as ASO1B), a substance commonly added to vaccines to initiate a stronger immune response.

In a 2015 randomized, placebo-controlled study published in the New England Journal of Medicine, Shingrix was more than 97 percent effective against shingles for adults ages 50 and older.

Covers a Wider Age Spectrum

A second study of Shingrix, also published in the New England Journal of Medicine in 2015, tested the vaccine on 70- to 80-year-olds exclusively, and found it was nearly 90 percent effective in preventing shingles. It was also found to be 89 percent effective against postherpetic neuralgia. A more recent review of clinical trials involving more than 2 million people ages 50 and older found Shingrix to be 85 percent more effective than Zostavax. The review, which was published in The BMJ in October 2018, noted a higher risk of side effects at the injection site, including redness and swelling, but no significant differences in more serious side effects.

Two-Shot Combination

Shingrix requires two shots, administered two to six months apart. High demand has created shortages, and many people have trouble getting their second shot within the six-month window.

Based on the effectiveness of other inactivated vaccines, Priya Sampathkumar, MD, an infectious disease specialist at Mayo Clinic in Rochester, MN, contends that even if you have to wait more than six months to get a second shot, it is still worthwhile.

If you cannot get your second shot within six months, get it as soon as you can. Visit Vaccine Finder to locate local sources of Shingrix.

Vulnerable Groups

Shingrix is not for everyone, says Dr. Nagel. For instance, people who have a history of an anaphylactic response to a previous vaccine or after an earlier dose of Shingrix should not get it.

People who currently have shingles should still get the vaccine, but wait until their doctor determines that they have completely recovered. People should be off any antiviral medication for at least 24 hours beforehand. Those who have a moderate to severe illness should wait until they recover. Women who are pregnant or nursing are advised against getting the vaccine by the US Centers for Disease Control and Prevention.

Web Extra

Read more information about how to pay for the Shingrix vaccine.