What Is Chickenpox (Varicella) Vaccine?
The chickenpox vaccine protects against chickenpox (varicella), a common and very contagious childhood viral illness.
Chickenpox Immunization Schedule
The chickenpox vaccine is given by injection when kids are between 12 and 15 months old. They receive a booster shot for further protection at 4 to 6 years of age.
Kids who are older than 6 but younger than 13, who have not had chickenpox, also may receive the vaccine, with the 2 doses given at least 3 months apart.
Kids 13 years or older who have not had either chickenpox or the vaccine need two vaccine doses at least 1 month apart.
Why Is the Chickenpox Vaccine Recommended?
The chickenpox vaccine prevents severe illness in almost all kids who are immunized. It’s up to 85% effective in preventing mild illness. Vaccinated kids who do get chickenpox generally have a mild case.
Possible Risks of Chickenpox Immunization
A rash can happen up to 1 month after the injection. It may last for several days but can disappear on its own without treatment. There is a very small risk of febrile seizures after vaccination.
Routine vaccination:
Minimum age: 12 months
Administer the primary dose at age 15 through 18 months and the second dose at age 4 through 6 years.
The second dose may be administered before age four years, provided at least 3 months have elapsed since the first dose. If the second dose was administered at least four weeks after the first dose, it can be accepted as valid.
The risk of breakthrough varicella is lower if given 15 months onwards.
Catch-up vaccination:
Ensure that all persons aged 7 through 18 years without ‘evidence of immunity’ have 2 doses of the vaccine.
For children aged 12 months through 12 years, the recommended minimum interval between doses is 3 months. However, if the second dose was administered at least 4 weeks after the first dose, it can be accepted as valid.
For persons aged 13 years and older, the minimum interval between doses is 4 weeks.
For persons without evidence of immunity, administer 2 doses if not previously vaccinated or the second dose if only 1 dose has been administered.
‘Evidence of immunity’ to varicella includes any of the following:
Documentation of age-appropriate vaccination with a varicella vaccine.
Laboratory proof of immunity or laboratory confirmation of disease.
Diagnosis or verification of a history of varicella disease by a health-care provider.
Diagnosis or verification of a history of herpes zoster by a health-care provider.