A large study of a vaccine for reducing the risk of herpes zoster, commonly known as shingles, confirms that the vaccine appears to be safe, a finding that may help improve its acceptance.
Shingles, which is caused by reactivation and replication of the dormant chickenpox virus (varicella-zoster virus) in individuals who previously had chickenpox, results in a painful blistering skin rash and, in some cases, a long-lasting, painful condition called postherpetic neuralgia. Older people are particularly vulnerable to shingles because immunity against varicella-zoster virus declines with age. An estimated 1 million episodes of shingles occurs in the United States annually.
Despite the availability of a vaccine (Zostavax) that appears to more than halve the risk of developing shingles since 2006, when it received US Food and Drug Administration (FDA) approval, uptake of the vaccination has been slow—even though the US Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices has recommended since 2008 shingles vaccination for healthy people 60 years and older and the FDA in March 2011 approved the use of the vaccine in individuals 50 to 59 years of age.
Although the main barriers to widespread use of shingles vaccine appear to be financial, another possible reason for the vaccine’s limited acceptance may be people’s concerns about the safety of this relatively new vaccine. The new study, appearing today in the Journal of Internal Medicine, examined adverse events after the shingles vaccine was administered to 193 083 adults 50 years and older from January 1, 2007, to December 31, 2008, and confirmed that the vaccine appears to be safe.
The researchers examined vaccination data retrieved from electronic health records collected from 8 managed care organizations participating in the Vaccine Safety Datalink collaboration between the CDC and integrated care organizations. Although they found a small increased risk of local allergic reactions (such as redness, swelling, and/or tenderness) at the site of the injection from 1 to 7 days after a patient receives the vaccine, there was no increased risk for strokes, cardiovascular events, meningitis, encephalitis, encephalopathy, Ramsay-Hunt syndrome, and Bell palsy.
“It’s good to know there is no serious adverse reaction to the zoster vaccine,” said study lead author Hung Fu Tseng, PhD, MPH, a research scientist with the Kaiser Permanente Southern California Department of Research and Evaluation in Pasadena, in a release. “The study supports the CDC’s Advisory Committee on Immunization Practices’ recommendation and reassures the general public that the vaccine is safe.”