Chickenpox vaccine does not appear to increase incidence of shingles, study finds

NEW YORK — The program to vaccinate children against chickenpox introduced in 1996 does not seem to be behind an increase in recent years in the number of cases of shingles, according to a new study.

The study, led by Centers for Disease Control and Prevention epidemiologists and published in the Dec. 3 issue of the Annals of Internal Medicine, looked at annual incidence of shingles, a painful condition caused by the same virus that causes chickenpox, among 2.85 million patients older than 65 years between 1992 and 2010 using Medicare data, finding 281,317 cases.

The researchers reported that they found no evidence of a statistically significant change in the rate of increase in shingles after the vaccination program was introduced, despite concerns that less-frequent exposure to the virus, known as varicella, would decrease immunity and thus increase the incidence of shingles, also known as herpes zoster.

"Age-specific [herpes zoster] incidence increased in the U.S. population older than 65 years even before implementation of the childhood varicella vaccination program," the researchers wrote. "Introduction and widespread use of the vaccine did not seem to affect this increase. This information is reassuring for countries considering universal varicella vaccination."