Vaccination
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.
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.
Recommendations for the Vaccine in Adults
Some experts suggest that every healthy adult without a known history of chickenpox be vaccinated. (About 90% of adults have a history of chickenpox so the numbers are likely to be low.) In any case, adults without such a history of infection should strongly consider vaccination if they are in the following groups:
- Adults 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.
- People who are in contact with people who have compromised immune systems.
- Nonpregnant women of childbearing age.
- Adolescents and adults living in households with children.
- International travelers.
As with other live-virus vaccines, the chickenpox vaccine is not recommended for the following:
- Women who are pregnant or who may become pregnant within 30 days of vaccination. Of note, an encouraging study suggested that pregnant women who were inadvertently vaccinated did not face a higher risk for birth defects in their offspring.
- People whose immune systems are compromised by disease or drugs (such as after organ transplantation). The vaccine is being studied, however, for its safety in some of these patients, particularly children with cancer or other high-risk conditions. Experts report that it is safe in children with acute lymphoblastic leukemia (ALL), who should receive two doses. Certain children who are HIV positive may be candidates for the vaccine. An inactivated varicella vaccine may be safe and effective in patients undergoing bone marrow transplants when given before and after the operation.
At present, most patients who cannot be vaccinated but are exposed to chickenpox are given immune globulin antibodies against varicella virus. This helps prevent complications of the disease if they become infected.