Prevention

Chickenpox (varicella) is a common contagious illness caused by a type of herpes virus. You can prevent chickenpox by getting the chickenpox vaccine(What is a PDF document?). Many states require that children entering day care and school have the vaccine unless they show proof of immunity (doctor's diagnosis or blood test results).

The vaccine works well and is recommended for:

• All healthy children 12 months of age and older who have not had chickenpox. It is given in 2 doses: the first at 12 to 15 months and the second at 4 to 6 years. Children age 12 and younger can get the MMRV shot(What is a PDF document?), which contains the vaccines for measles, mumps, and rubella as well as varicella. Talk to your doctor about the pros and cons of the MMRV shot.
• Older children and adults who have not had chickenpox or the chickenpox vaccine.
• People who do not know whether they had chickenpox as a child. It is safe for them to receive the chickenpox vaccine even if they had chickenpox in the past.
• People who have not had chickenpox or the vaccine and have been exposed to someone ill from the virus.

In rare cases, people who have had the vaccine still get chickenpox. If this happens, you will probably get a milder form of the illness, with fewer blisters and symptoms. This is called a breakthrough infection. Talk with your doctor if you have questions or concerns about the vaccine. For more information on routine immunizations, see the topic Immunizations.

Some people can't get the chickenpox vaccine to help prevent chickenpox. But they may be able to get a shot of chickenpox antibodies instead. The antibodies work best when they are given soon after exposure to the virus. If you have been in contact with a person who has chickenpox and are not sure whether you are immune, talk with your doctor about whether you should have either the chickenpox vaccine or antibodies.

You can help prevent chickenpox by avoiding close contact with people infected with the virus. This is particularly important if you have an impaired immune system. But the virus can spread from an infected person even before symptoms develop. Chickenpox spreads quickly among people who are in close contact with each other in confined spaces, such as children in small classrooms or people who share bedrooms. It may be hard to prevent chickenpox from spreading after the rash develops.

Women who want to become pregnant and have never had chickenpox should think about being tested for immunity or get the vaccine to prevent complications of chickenpox during pregnancy.

Don't expose children to chickenpox

Parents should not intentionally expose children to chickenpox. It is not safer for children to have the infection when they are younger than when they are older. Even young children can have serious (though rare) complications from the infection, including pneumonia or encephalitis. And it is not possible to know which children will develop complications.

Prevent the spread of chickenpox

If you or your child has chickenpox, don't return to work, school, or day care until after all blisters have crusted over, usually about 10 days after the first symptoms start. To help prevent spreading chickenpox, stay away from people who aren't immune.