Varicella is a highly contagious viral illness caused by infection with the varicella zoster virus (VZV). The disease causes fever, sore throat, and a distinctive, itchy rash with fluid-filled blisters that later forms scabs. The virus is transmitted by the spread of airborne droplets or direct contact with skin lesions. Complications of chickenpox may include bacterial infections of the skin, pneumonia, or, less commonly, inflammation of the brain.
Before the vaccine was available, an estimated 3.7 million cases of chickenpox occurred in the United States every year, resulting in nearly 9000 hospitalizations and approximately 100 deaths.
Timing and dose — In the United States, VZV vaccine is recommended for all children at 12 to 18 months of age (show table 1). A second dose is recommended at 4 to 6 years of age. A combination measles, mumps, rubella, and varicella vaccine (MMRV, ProQuad) may be used in children between 12 months and 12 years. The VZV vaccine is not needed if a child develops typical chickenpox disease before the vaccine is given.
Chickenpox vaccine precautions — The varicella vaccine contains live weakened VZV, thus it is not recommended for children with a weakened immune system or during moderate to severe illness. The vaccine should be delayed in a child who has recently received a blood transfusion or other blood product. The vaccine is not recommended for children who have a severe allergy to neomycin or gelatin (show table 5). The most common side effects of the VZV vaccine are redness or soreness at the injection site and a mild rash (about five spots).
Chickenpox vaccine effectiveness — The chickenpox vaccine protects 70 to 90 percent of people who get it. However, about 1 percent of people who are given the vaccine develop chickenpox; in these people, the infection is usually mild, fever does not usually occur, and skin blisters do not develop.
Before the vaccine was available, an estimated 3.7 million cases of chickenpox occurred in the United States every year, resulting in nearly 9000 hospitalizations and approximately 100 deaths.
Timing and dose — In the United States, VZV vaccine is recommended for all children at 12 to 18 months of age (show table 1). A second dose is recommended at 4 to 6 years of age. A combination measles, mumps, rubella, and varicella vaccine (MMRV, ProQuad) may be used in children between 12 months and 12 years. The VZV vaccine is not needed if a child develops typical chickenpox disease before the vaccine is given.
Chickenpox vaccine precautions — The varicella vaccine contains live weakened VZV, thus it is not recommended for children with a weakened immune system or during moderate to severe illness. The vaccine should be delayed in a child who has recently received a blood transfusion or other blood product. The vaccine is not recommended for children who have a severe allergy to neomycin or gelatin (show table 5). The most common side effects of the VZV vaccine are redness or soreness at the injection site and a mild rash (about five spots).
Chickenpox vaccine effectiveness — The chickenpox vaccine protects 70 to 90 percent of people who get it. However, about 1 percent of people who are given the vaccine develop chickenpox; in these people, the infection is usually mild, fever does not usually occur, and skin blisters do not develop.
