Chickenpox immunization for children

Chickenpox is a highly contagious viral infection, characterized by an itchy rash. The infection usually is mild in healthy children. But, it can be more serious for adolescents, adults, and people of all ages who have certain conditions or weakened immune systems. If contracted during pregnancy, chickenpox can cause severe symptoms and pose significant risk to the fetus.

The chickenpox vaccine (Varivax) is a "live" vaccine. It contains a weakened form of the virus that causes chickenpox. The vaccine sometimes is given in combination with the MMR (measles, mumps and rubella) vaccine.


Recommendations/dose
Children ages 12 months to 18 months routinely are vaccinated for chickenpox with one dose of the vaccine. Other recommendations include:
Children ages 18 months to 12 years who haven't yet received the vaccine should get one dose.
Children ages 13 years or older who haven't yet received the vaccine should get two doses, with the second given four to eight weeks after the first.
In children who haven't received the vaccine and are exposed to the virus, you may be able to prevent or decrease the severity of symptoms by giving one dose of the vaccine within three to five days of exposure.
A combination vaccine for measles, mumps, rubella and varicella (MMRV) is now available to help reduce the number of shots a child receives at one time. If the chickenpox vaccine isn't given at the same time as the measles, mumps and rubella (MMR) vaccine, wait at least four weeks between the two immunizations. And, you should wait at least four weeks after an MMR immunization before receiving the combination MMRV vaccination.


Effectiveness/booster
The vaccine is up to 85 percent effective in preventing chickenpox. The few children who develop chickenpox despite receiving the vaccine usually have only a mild case. Length of protection is uncertain. But, the vaccine appears to be long-lasting. A booster isn't currently recommended.

Side effects
Side effects are uncommon. When they do occur, they're usually mild. They may include pain, tenderness, redness or swelling at the injection site and a fever of 102 degrees F or higher. Use acetaminophen -- not aspirin or aspirin-containing products -- to treat pain or fever. Remember, you should never give aspirin to anyone age 19 or younger, unless directed by a doctor. It's been linked to Reye's syndrome, a rare but sometimes fatal condition.
A mild chickenpox-like rash may develop at the injection site or elsewhere five to 26 days after the vaccine. Rarely, the rash may spread the chickenpox virus to others. Other rare side effects may include:

an allergic reaction
pneumonia
blood clotting problems
neurological reactions
Who should wait to receive the vaccine? Your child's doctor may decide to postpone the vaccine if your child:

has a moderate to severe acute illness
received a blood product containing an antibody (such platelets, a blood transfusion or an immune globulin) within the last three to 11 months (depending on which product was given)
will receive such a product in the next two weeks

Who shouldn't get the vaccine?
Your child shouldn't receive the vaccine if he or she has had a severe allergic reaction to a prior dose of the vaccine, gelatin or the antibiotic neomycin. Your child's doctor also may caution against the vaccine if your child's immune system isn't functioning properly.