What is the Varicella (“Chickenpox”) Vaccine?
Since the introduction of the varicella vaccine into the United States in 1995, the number of people infected with chickenpox has decreased from about 4 million per year to about 400,000 per year. Although this represents a 90 percent decrease in the incidence of infection, chickenpox infections still occur fairly frequently in the United States. In an attempt to completely eliminate chickenpox, a second dose of varicella vaccine is now recommended for children between 4 and 6 years of age (similar to the second dose of MMR vaccine).
The Varicella vaccine is designed to protect an individual from chickenpox, which is caused by the varicella-zoster virus. Varicella (chickenpox) is a highly contagious viral infection that causes an individual to develop itchy red blisters over the entire body. The infection can be spread through the air by sneezing or coughing, or by direct contact with the blisters. Varicella infections are often mild and resolve within five to ten days. However, it is uncomfortable and can be serious at times. In addition to the blisters, typical symptoms include fever, tiredness, loss of appetite, and headache. Approximately 1 out of every 1,000 children infected with varicella may develop more severe complications. In addition, approximately 1 out of every 50 women infected with varicella during their pregnancy may deliver children with birth defects.
The Varicella vaccine is made from the live, but weakened varicella virus. When administered it produces an immune response in the body that protects against chickenpox. The chickenpox vaccine was licensed for use in the United States in 1995. Since then, the vaccine has become widely used. Prior to the introduction of the vaccine, there were approximately 11,000 hospitalizations and 100 deaths per year in the U.S
Who should receive a Chickenpox vaccine?
The Centers for Disease Control and Prevention (CDC) recommends two doses of chickenpox vaccine for anyone without evidence of immunity to varicella. However, pregnant women should not receive the chickenpox vaccine.
How is the Varicella vaccine administered?
The Varicella vaccine is administered subcutaneously in two doses for children ages 12 months through 12 years. The first dose is administered between 12 and 15 months old, and a second dose at 4 to 6 years old. The CDC recommends that each dose is administered at least 3 months apart. It is recommended that people 13 years of age and older who have never had chickenpox or have not received the chickenpox vaccine should get two doses, administered at least 4 to 8 weeks apart.