Most people view chickenpox as a disease of childhood–or, as the vaccine against it is increasingly used, as a disease of the past. But varicella zoster, the herpes virus that causes chickenpox, is sneaky. Even after a varicella infection clears, the virus hides in the nerve cells, inactive. In about 20% of people who have had chickenpox, the virus will reappear later in life to cause shingles, a disease of severe pain and blisters on the body or face. Blisters on the face can cause problems with vision and hearing, while the spread of the disease to the body’s internal organs can cause serious damage, including encephalitis (inflammation in the brain).
A vaccine against shingles was approved by the U.S. Food and Drug Administration in 2006 after it was shown to be effective (in clinical trials, the vaccine reduced the risk of shingles by 50%). Recently, a long-term follow-up study of 38,000 participants from the trial that led to its approval also demonstrated its long-term safety. (The study, from the Annals of Internal Medicine, can be found here.)
The use of the vaccine, however, does not reflect the data on its safety or effectiveness: a separate study, also in the Annals of Internal Medicine, indicated that despite the vaccine being available since 2006 and recommended since 2008 by the Advisory Committee on Immunization Practices for all adults 60 or older, early use of the vaccine has been between only 2% and 7% in the United States. (That study can be found here.) More