Receiving the herpes zoster vaccine was associated with a 55 percent reduced risk of developing shingles, according to a Kaiser Permanente study of 300,000 people that appears in the current issue of the Journal of the American Medical Association.
This retrospective study observed the outcomes of the effectiveness of the herpes zoster vaccine in a large, diverse population of men and women ages 60 years and older. Researchers found a significant reduced risk of shingles across all sub-groups -- those who are healthy as well as those with chronic conditions including diabetes or heart, lung or kidney diseases.
These study findings differ from the clinical trial of the vaccine, which observed its effectiveness on 38,000 participants 60 years of age and older and found it less effective for people older than 75. This new study found a 55 percent reduced risk of shingles among both adults 60 years and older, as well as adults 75 years and older who received the vaccine.
These findings support Centers for Disease Control and Prevention recommendations to offer the vaccine to eligible patients of all ages, including those over 75. Researchers note that additional examination of the vaccine's effect in the oldest group should continue. The herpes zoster vaccine was licensed in 2006, but uptake in the United States remains low: about 10 percent in 2009 in adults 60 years and older.
"Our study shows the vaccine has the potential to prevent tens of thousands of cases of shingles, a painful, lingering disease," said study lead author Hung Fu Tseng, PhD, MPH, a research scientist with the Kaiser Permanente Department of Research & Evaluation in Pasadena, Calif. "We suggest clinicians follow the CDC's recommendations to talk to their patients about the option of vaccination against this serious condition."
There are more than 1 million episodes of shingles every year in the United States. Shingles is a painful condition that can last months or years and can seriously impact quality of life. Shingles is caused by the dormant chickenpox virus, which stays in the body after a person has recovered from chickenpox. The virus can reactivate and replicate and cause shingles and damage to the nerve system. The elderly are especially vulnerable because as we age, our immunity against the virus that causes shingles declines.
"The risk of developing shingles during a lifetime is about 30 percent. It is therefore reassuring to confirm results of the original clinical trial that herpes zoster vaccine is effective at preventing this painful disease," said study co-author Rafael Harpaz, MD, MPH, an epidemiologist with the Centers for Disease Control and Prevention's National Center for Immunization and Respiratory Diseases. "Although that trial was well done, one cannot be sure a vaccine works outside a research setting until you evaluate it in routine medical practices. In addition, our study also provided new information that the vaccine worked to prevent shingles involving the eye, which can result in very serious complications."
Researchers conducted a retrospective observational study that looked at 75,761 vaccinated and 227,283 unvaccinated male and female members of Kaiser Permanente in Southern California from 2007 to 2009, using electronic health records to compare the incidence of shingles of the vaccinated and unvaccinated populations. Results remained after taking into account differences in sex, race, chronic diseases, and prior utilization.
This is the latest in a series of published Kaiser Permanente studies undertaken to better understand vaccine effectiveness and safety. Dr. Tseng published another study in JAMA that found the pneumococcal pneumonia vaccination is not associated with a reduced risk of heart attacks or strokes. Another Kaiser Permanente study found the combination vaccine for measles, mumps, rubella and chickenpox (MMRV) is associated with double the risk of febrile seizures for 1- to 2-year-old children compared to same-day administration of the separate vaccine for MMR (measles, mumps, rubella) and the varicella (V) vaccine for chickenpox. Other recent published Kaiser Permanente studies found children of parents who refuse vaccines are nine times more likely to get chickenpox and 23 times more likely to get whooping cough compared to fully immunized children. A study published last year found that herpes zoster, also known as shingles, is very rare among children who have been vaccinated against chickenpox.
Co-authors of the paper include Hung Fu Tseng, PhD, MPH; Ning Smith, PhD; Lina S. Sy, MPH; and Steven J. Jacobsen, MD, PhD; with Kaiser Permanente Department of Research & Evaluation; and Rafael Harpaz, MD, MPH, and Stephanie R. Bialek, MD, MPH, with the Center for Disease Control and Prevention National Center for Immunization and Respiratory Diseases, Division of Viral Diseases.