The varicella vaccine, also known as the chickenpox vaccine, is an active immunizing agent used to prevent infection caused by the varicella-zoster virus (VZV), which causes chickenpox. It typically contains a live, attenuated (weakened) form of the virus that triggers the body's immune system to produce protection (antibodies) against the virus without causing the disease itself. Key points about the varicella vaccine:
- It is indicated for active immunization against varicella in individuals 12 months of age and older.
- The vaccine is given by injection just under the skin, typically as two doses for better protection.
- For children aged 12 months to 12 years, two doses are recommended: the first dose at 12 to 15 months of age, and the second dose at 4 to 6 years. For adolescents and adults, two doses are administered at least 4 weeks apart.
- One dose can prevent about 95% of moderate chickenpox cases and 100% of severe cases; two doses provide improved protection.
- The vaccine can be given as a single antigen (only varicella) or in a combination vaccine with measles, mumps, and rubella (MMRV).
- The vaccine has been shown to be effective over the long term, with antibody persistence and significant reduction in disease incidence.
- It is generally safe, with mild side effects such as pain at the injection site or mild rash; severe side effects are rare.
Immunization against chickenpox is recommended for anyone 12 months and older who has not had chickenpox before to prevent illness and complications from the disease.
