An End to Chickenpox?

Posted by Pharmacist on July 12, 2011

Two-Dose Varicella Vaccine May Help Eradicate Chickenpox

The February 2011 issue of the Journal of Infectious Diseases published a study that found two doses of the varicella vaccine prevented chickenpox 98.3 percent of the time, compared to just 86 percent of the time in those who received only one dose.

One dose has been the standard since 1995, when the Centers for Disease Control and Prevention (CDC) recommended it for children between the ages of 1 and 13 years old. Pharmacy Today notes the practice helped reduce chicken pox occurrences by 90 percent. Yet even with the large-spread use of the varicella vaccination there were still breakthrough illnesses reported in immunized patients. This prompted the CDC to recommend an additional dose of the vaccine for children between the ages of 4 and 6.

While prior studies have linked two doses of the vaccine with greater antibody levels than a single dose, the study in the February 2011 Journal of Infectious Diseases was the first of its kind to review the effectiveness of two doses on the general population. It found children older than 4 years of age who had two doses of the vaccine were 95 percent less likely to develop varicella.

These findings may reduce the likelihood of developing chickenpox for children in the United States as well as the rest of the world. The authors of the study wrote: “The effects of this 2-dose policy in the United States will also have important implications for national immunization programs in other countries that use varicella vaccine.” Over time, if the two-dose system is implemented successfully, we may see the end of chickenpox all together.

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