The varicella vaccine helps protect against chickenpox Chickenpox Chickenpox is a highly contagious viral infection with the varicella-zoster virus that causes a characteristic itchy rash, consisting of small, raised, blistered, or crusted spots. Chickenpox... read more 
(varicella), a very contagious infection caused by the varicella-zoster virus. It causes an itchy rash that looks like small blisters with a red base. In some people, the brain, lungs, and heart can become infected, resulting in serious illness or death. The virus remains in the body after the illness has resolved. If it is reactivated, it can cause shingles Shingles Shingles is a painful skin rash caused by a viral infection that results from reactivation of the varicella-zoster virus, the virus that causes chickenpox. What causes the virus to reactive... read more 
years later.
The varicella vaccine contains weakened, live varicella virus. There are two formulations:
Standard dose varicella vaccine
Combination measles-mumps-rubella-varicella (MMRV) vaccine
For more information, see the Centers for Disease Control and Prevention's (CDC) Chickenpox vaccine information statement.
(See also Overview of Immunization Overview of Immunization Immunization (vaccination) helps the body defend itself against diseases caused by certain bacteria or viruses. Immunity (the ability of the body to defend itself against diseases caused by... read more .)
Administration of Varicella Vaccine
Vaccination against varicella is part of the routine vaccination schedule recommended for children (see CDC: Child and Adolescent Immunization Schedule by Age). The vaccine is given as an injection under the skin. Two doses are given: at age 12 to 15 months and at age 4 to 6 years. It is also recommended for all adolescents and adults who have not had chickenpox or the vaccine. It is given to them in two doses at least 4 weeks apart (see CDC: Chickenpox Vaccination: What Everyone Should Know).
Certain conditions may affect whether and when people are vaccinated (see also CDC: Who Should NOT Get Vaccinated With These Vaccines?). If people have a temporary illness, doctors usually wait to give the vaccine until the illness resolves.
Because the vaccine contains live virus, it is not given to pregnant women, people with a weakened immune system, or people with cancer of the bone marrow or lymphatic system.
Side Effects of Varicella Vaccine
The varicella vaccine is very safe, and common side effects are mild. They include pain, swelling, and redness at the injection site and fever and temporary joint pain and stiffness.
Very occasionally, a chickenpox-like rash develops. People who develop this rash after the vaccine should diligently avoid contact with people who have a weakened immune system until after the rash resolves.
Taking aspirin and related drugs (salicylates) after vaccination can cause a rare but serious disorder called Reye syndrome Reye Syndrome Reye syndrome is a very rare but life-threatening disorder that causes inflammation and swelling of the brain and impairment and loss of function of the liver. The cause of Reye syndrome is... read more in children under 16 years old. Thus, such children should not be given these drugs for 6 weeks after vaccination.
More Information
The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
Centers for Disease Control and Prevention (CDC): Chickenpox vaccine information statement
European Centre for Disease Prevention and Control (ECDC): Varicella: Recommended vaccinations
