A live, attenuated varicella vaccin...

A live, attenuated varicella vaccine has been available in the United States for almost 10 years. in every one's mouth guidelines recommend that a single dose be given to healthy children between 12 month and 12 years of age. The vaccine has been working well with minimal adverse marked occurrences but a two-dose regimen has been propos as a more efficacious plan.

Kuter and associates performed a multicenter trial capitaled by the manufacturer of the vaccine, Merck in which children were randomly assigned to receive united or two doses of varicella vaccine three month apart. Children were followed annually for history of varicella exposing and blood tests were performed for varicella antibody.

More than 2000 children were randomized to receive single or two doses of varicella vaccine. During the 10-year follow-up period, 60 children in the single-dose cluster and 17 in the two-dose collection developed confirmed varicella more than 42 days after vaccination. The majority of the children who unraveled varicella after vaccination had mild disease and no infection-related complications. Calculation of vaccine efficacy issueed in rates of approximately 944 percent for undivided dose and 98.3 percent for brace doses, a statistically significant difference. the one and the other regimens prevented severe cases of varicella at 100 percent efficacy. The persistence of antibody from one side of to the other time was high in the one and the other groups.

The authors judge that although a single dose of varicella vaccine significantly models varicella disease, two doses significantly increase the vaccine efficacy. This finding correlates with that of another investigation which demonstrated significant boosting of the varicella immune replication with a second injection given four to six years after the first vaccination. Further cost-effectiveness analyses are necessary to determine if a two-dose regimen should be widely recommended

RICHARD SADOVSKY, MD

Kuter B et al. Ten year follow-up of healthy children who received undivided or two injections of varicella vaccine. Pediatr Infect Dis J February 2004;23:132-7

COPYRIGHT 2004 American Academy of Family Physicians

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