Each year, more than 1 million U.S. adults develop shingles -- a painful contagious rash caused by the dormant chickenpox virus that can reactivate and replicate, damaging the nerve system. The elderly are especially vulnerable because immunity against the virus declines with age.
This study examined adverse events after the zoster vaccine (shingles vaccine) was administered to 193,083 adults age 50 and older from Jan. 1, 2007, to Dec. 31, 2008. Vaccination data were retrieved from electronic health records and collected from eight managed care organizations.
The researchers found a small increased risk of local reactions from one to seven days after vaccination. These findings corroborate clinical trials of the vaccine in which there was evidence of a minor local reaction at the injection site in the form of redness and pain, the study said.
The study found no increased risk for cerebrovascular diseases, cardiovascular diseases, meningitis, encephalitis, encephalopathy, Ramsay-Hunt syndrome or Bell's palsy.
"It's good to know there is no serious adverse reaction to the zoster vaccine. The study supports the Centers for Disease Control's Advisory Committee on Immunization Practices recommendation and reassures the general public that the vaccine is safe," said lead author Hung Fu Tseng, a research scientist with the Kaiser Permanente Southern California Department of Research & Evaluation in Pasadena, Calif.
The findings were published in the Journal of Internal Medicine.