Giving people the herpes zoster vaccine was linked to a 55 per cent reduction in risk of developing shingles according to a Kaiser Permanente study involving 300,000 older American GP patients, suggesting that vaccinating eligible people could prevent tens of thousands of cases of shingles in the US.

You can read about the retrospective cohort study, led by Dr Hung Fu Tseng, a research scientist with the Kaiser Permanente Department of Research and Evaluation in Pasadena, California, in the 12 January online issue of JAMA.

The findings support the US Centers for Disease Control and Prevention (CDC) recommendation that the vaccine be offered to eligible patients of all ages, including those over 75.

Tseng told the press that:

“Our study shows the vaccine has the potential to prevent tens of thousands of cases of shingles, a painful, lingering disease.”

“We suggest clinicians follow the CDC’s recommendations to talk to their patients about the option of vaccination against this serious condition,” said Tseng.

Shingles (herpes zoster) is caused by the chickenpox virus (varicella zoster), which stays dormant in the nervous system after a person has recovered from chickenpox, but then flares up again, often many years later, as a painful skin rash with blisters, usually in a line on one side of the torso.

There are more than a million cases of shingles every year in the US. The condition affects mainly older people, as immunity against the virus declines; but it can also affect people under a lot of stress or who have weakened immunity. The condition can last months, even years, and seriously impair quality of life. It can also damage the nerves.

The herpes zoster vaccine has demonstrated efficacy against shingles in clinical trials, but has not been tested under everyday conditions such as in general practices.

Using electronic health records, Tseng and colleagues compared the incidence of shingles among a diverse population of 75,761 vaccinated, and 227,283 unvaccinated, men and women aged 60 and over who were members of Kaiser Permanente in Southern California between 2007 and 2009. The participants were community-dwelling, had healthy immune systems and those who were vaccinated had received their vaccine in a GP setting.

The results showed a significant reduced risk of shingles across all sub-groups, including healthy patients and those with chronic conditions such as diabetes, heart, lung or kidney diseases.

The results remained the same after the researchers took into account differences in gender, race, chronic diseases and prior use.

The findings differ from those of the clinical trial of the vaccine that had involved 38,000 people aged 60 and over and found it to be less effective for those aged 75 and over.

Tseng and colleagues found that the 55 per cent reduction in risk of developing shingles was true for people of all ages, including those over 75, who received the vaccine.

They said the findings support the CDC’s recommendation that the vaccine be offered to eligible patients of all ages, including those over 75.

Co-author Dr Rafael Harpaz, an epidemiologist with the CDC’s National Center for Immunization and Respiratory Diseases, said there was a 30 per cent risk of developing shingles during one’s lifetime.

“It is therefore reassuring to confirm results of the original clinical trial that the herpes zoster vaccine is effective at preventing this painful disease.”

“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,” he added.

As well as affecting the torso, shingles can also appear on the face and affect the eyes and result in very serious complications. Harpaz said their study found new information that the vaccine works to prevent shingles involving the eye.

In a statement, Kaiser said that a study published last year found that shingles is very rare among children who have been vaccinated against chickenpox.

“Herpes Zoster Vaccine in Older Adults and the Risk of Subsequent Herpes Zoster Disease.”
Hung Fu Tseng, Ning Smith, Rafael Harpaz, Stephanie R. Bialek, Lina S. Sy, and Steven J. Jacobsen.
JAMA, 305(2):160- 166, published online 12 Jan 2011.

Additional source: Kaiser Permanente (press release, 11 Jan 2011).

Written by: Catharine Paddock, PhD