The expert panel that makes vaccine recommendations and policy for children and adults in the U.S. has voted to recommend a chickenpox (varicella) vaccine booster for all children.

The chickenpox vaccine is relatively new (it was licensed in 1995), and it has been unclear for years whether immunity would decrease and a booster dose would be needed. Data now show that 15 to 20 percent of people who receive one dose of the vaccine are not fully protected, and immunity may not last into adulthood, when chickenpox is much more severe.

Children currently receive the varicella vaccine at 12-18 months of age. It is recommended that all children receive a second booster dose at age 4-6 years, along with the other booster vaccines given at that time.

It is also recommended that children, adolescents, and adults who have received one dose of the vaccine also get a booster dose. For children less than 13 years old, the second dose should be at least 3 months after the first; for children 13 and older and adults, the second dose can be given 4 weeks after the first.

Recommendations of the expert panel do not become official vaccine policy until published by the CDC. Insurance companies usually do not start covering a vaccine until well after it is officially published, but since varicella vaccine is already a covered vaccine, most will probably cover additional doses as well, since most do not track the number of vaccines a person has received.