Varicella vaccine effective against chicken pox

The varicella vaccine has been largely successful in neutralizing chicken pox, scientists say. The 14-year study by the Kaiser Permanente Vaccine Study Center followed 7,585 children who were vaccinated in 1995, when they were 12 to 23 months old, to assess the long-term effectiveness of the vaccine and the impact on the epidemiology of varicella (chicken pox) and herpes zoster (shingles). Researchers also observed the impact of the second dose of varicella vaccine, introduced in 2006. The varicella vaccine was licensed in the United States in 1995, and recommended soon after by the Advisory Committee on Immunization Practices for routine administration to children. Prior to that, chicken pox was ubiquitous, with more than 90 percent of young people experiencing infection by the age of 20. Over the entire follow-up period, the incidence rate of chicken pox in this cohort was 9 to 10 times lower than corresponding rates in unvaccinated children of the...