Two Is Better Than One

Study finds two-dose chicken pox vaccination is more effective than one dose

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Researchers from Yale University and Colombia University recently tested the efficacy of a two dose vaccination for varicella, also known as chickenpox.

Appearing in the February 1 issue of the Journal of Infectious Diseases, the study provides evidence that the two-dose vaccine, which was recommended by the Centers for Disease Control (CDC) in 2006, is more effective than the previously recommended single dose.

Although chicken pox is a fairly harmless disease for most children, it can be much more severe, even deadly, for adolescents and adults. The disease is usually characterized by the development of a skin rash often in conjunction with a fever. For some, however, chicken pox can lead to bacterial infections of the skin, brain swelling, and pneumonia.

The study, conducted by Eugene D. Shapiro, M.D., and colleagues, compared the efficacy of the two-dose vaccination regimen to that of the one-dose regimen. After analyzing the outcomes of 140 cases, the researchers found that two doses prevented chicken pox in 98.3 percent of cases, while the one-dose treatment prevented the disease in merely 86.0 percent of cases. The chances of contracting chicken pox were reduced by 95 percent in those children who received two doses, according to Dr. Shapiro.

While the CDC already recommends the two-dose vaccination, much of the world receives only one dose. This study, the first of its kind to examine the efficacy of the two doses, suggests that other countries should adopt the two-dose vaccination regimen.

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Review Date: 
January 5, 2011
Last Updated:
January 6, 2011