Varicella (chickenpox) vaccine given to children 12 months of age and older has resulted in significant protection from the disease for infants as well, according to a study in the December 2011 issue of Pediatrics and published online Nov. 28. Before the U.S. began vaccinating children 12 months of age and older against varicella in 1995, infants were four times more likely to die from a varicella infection compared to children ages 1 to 14 years.
In the study, “Varicella in Infants After Implementation of the U.S. Varicella Vaccination Program,” researchers at the U.S. Centers for Disease Control & Prevention tracked cases of varicella in infants from 1995 to 2008.
Infant varicella disease in children under 1 year of age declined 89.7 percent during that time period, even though infants are not eligible for the vaccine. Infants ages 0 to 5 months had milder clinical disease compared to those ages 6 to 11 months, possibly because they were protected by maternal antibodies.
Authors conclude that the varicella vaccination program has resulted in substantial indirect benefits for infants. Because exposure to the virus continues to occur, improving vaccination coverage in all age groups will further reduce the risk for infants, study authors conclude.
