VARIVAX is indicated for vaccination against varicella in individuals 12 months of age and older.
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Children 12 months to 12 years of age should receive a 0.5-mL dose administered subcutaneously; if a second 0.5-mL dose is administered, it should be given a minimum of 3 months later. |
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Adolescents and adults 13 years of age and older should receive a 0.5-mL dose administered subcutaneously at elected date and a second 0.5-mL dose 4 to 8 weeks later. |
Varicella Disease
Varicella, caused by varicella-zoster virus (VZV), usually occurs in childhood and is characterized by a generalized pruritic vesicular exanthem and fever.1 Constitutional symptoms that develop after onset of rash include malaise, pruritus, anorexia, and listlessness. Skin manifestations in varying stages of evolution consist of maculopapules, vesicles, and scabs. At first, the lesions contain clear fluid, pustulating and scabbing over a short period of time.
Rash initially appears on the trunk and face, quickly spreading to other areas of the body. Successive crops of lesions generally continue over a period of 2 to 4 days. Crusts completely fall off within 1 to 2 weeks after infection begins and can leave a slightly depressed area in the skin.
Transmission most likely occurs via respiratory droplets. The virus is believed to replicate at the site entry in the nasopharynx and in regional lymph nodes. Varicella is usually contagious from 1 to 2 days before onset of rash through the first 4 to 5 days, or until lesions have formed crusts.
The risk of complications and death from chickenpox is 10 to 20 times higher for adolescents and adults than for children. The most common potentially severe complications of chickenpox are bacterial skin infections, pneumonia, and encephalitis. Some infections can rarely result in necrotizing fasciitis. Varicella-associated bacterial skin infections with group A ß-hemolytic streptococcus can have a mortality rate of up to 70% when compounded by toxic shock.
Taken from www.merckvaccines.com