Medical Health Encyclopedia

A live-virus vaccine (Varivax) produces persistent immunity against chickenpox. Data show that the vaccine can prevent chickenpox or reduce the severity of the illness even if it is used within three days, and possibly up to five days, after exposure to the infection.

Recommendations for the Vaccine in Children. The vaccine against chickenpox is now recommended in the US for all children between the ages of 18 months and adolescence who have not yet had chickenpox. Children are given one dose of the vaccine. Two doses one to two months apart are given to people over 13 years of age. To date, more than 75% of children have been vaccinated.

Experts recommend that the chickenpox vaccine be given at the same time as the measles-mumps-rubella (MMR) vaccine or that there is a delay of at least a month between the two vaccinations. (If the chickenpox vaccination is given within that 30 day period--but not at the same time--there is a higher risk for a breakthrough infection later on.)

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A chickenpox vaccine is part of the routine immunization schedule. It is about 100% effective against moderate or severe illness, and 85 - 90% effective against mild chickenpox. Parents often express concern that the immunity from the vaccine might not last. The chickenpox vaccine, though, is the only routine vaccine that does not require a booster.

Recommendations for the Vaccine in Adults.

Some experts suggest that every healthy adult without a known history of chickenpox be vaccinated. In general, however, the following adults should consider vaccinations:

• Older people without a history of chickenpox and who are at high risk of exposure or transmission (e.g., hospital or day care workers, parents of young children).
• People who live or work in environments in which viral transmission is likely.
• Nonpregnant women of childbearing age.
• Adolescents and adults living in households with children.
• International travelers.