Prevention

The chickenpox (varicella) vaccine is the best way to prevent chickenpox. Experts from the CDC estimate that the vaccine provides complete protection from the virus for nearly 98% of people who receive both of the recommended doses. When the vaccine doesn't provide complete protection, it significantly lessens the severity of chickenpox.

The chickenpox vaccine (Varivax) is recommended for:

• Young children. In the United States, children receive two doses of the varicella vaccine — the first between ages 12 and 15 months and the second between ages 4 and 6 years — as part of the routine childhood vaccination schedule.

  The vaccine can be combined with the measles, mumps and rubella vaccine, but for some children between the ages of 12 and 23 months, the combination may increase the risk of fever and seizure from the vaccine. Discuss the pros and cons of combining the vaccines with your child's doctor.

• Unvaccinated older children. Children ages 7 to 12 years who haven't been vaccinated should receive two catch-up doses of the varicella vaccine, given at least three months apart. Children age 13 or older who haven't been vaccinated should also receive two catch-up doses of the vaccine, given at least four weeks apart.

• Unvaccinated adults who've never had chickenpox and are at high risk of exposure. This includes health care workers, teachers, child care employees, international travelers, military personnel, adults who live with young children and all women of childbearing age.

  Adults who've never had chickenpox or been vaccinated usually receive two doses of the vaccine, four to eight weeks apart. If you don't remember whether you've had chickenpox or the vaccine, a blood test can determine your immunity.

The chickenpox vaccine isn't approved for:

• Pregnant women
• People who have weakened immune systems, such as those who are infected with HIV, or people who are taking immune-suppressing medications
• People who are allergic to gelatin or the antibiotic neomycin

Talk to your doctor if you're unsure about your need for the vaccine. If you're planning on becoming pregnant, consult with your doctor to make sure you're up to date on your vaccinations before conceiving a child.

Is it safe and effective?

Parents typically wonder whether vaccines are safe. Since the chickenpox vaccine became available, studies have consistently found it to be safe and effective. Side effects are generally mild and include redness, soreness, swelling and, rarely, small bumps at the site of the shot.