Double Doses Of Chicken Pox Vaccine Most Effective
Posted Jan 10 2011 6:02pm
When vaccinating children against varicella (chicken pox), researchers at Yale School of Medicine have found, two doses are better than one. In fact, the odds of developing chicken pox were 95% lower in children who had received two doses of the vaccine compared with those who had received only one dose.
Published in the Feb. 1 issue of Journal of Infectious Diseases, the study was led by Dr. Eugene D. Shapiro, professor in the Department of Pediatrics at Yale, and his colleagues at Yale and Columbia universities.
The Centers for Disease Control and Prevention (CDC) began recommending a single dose of chicken pox vaccine for children ages 1 to 13 in 1995. The chicken pox rate fell drastically and studies showed that the effectiveness of one dose was 86%. But there was still a high rate of breakthrough illness in immunized children. The CDC changed the immunization policy for chicken pox in 2006, adding a second dose for children ages 4 to 6. In this study, Shapiro and his team showed that the effectiveness of two doses is 98.3%.