Varicella (Chickenpox)

Child with varicella including lesions on the palate

What is Varicella?
Although generally mild, varicella (chickenpox) is a highly contagious virus. It causes a blister-like rash, itching, tiredness, and fever. Chickenpox can be serious, especially in babies, adults, and people with weakened immune systems. These individuals may have more severe symptoms and may be at higher risk for complications. Chickenpox spreads easily from infected people to others who have never had chickenpox or received the chickenpox vaccine. The virus spreads in the air through coughing or sneezing. It can also be spread by touching or breathing in the virus particles that come from chickenpox blisters. Once the varicella virus infects the body, it remains there for life and may reappear as shingles, particularly in people over 60 years old.

The virus can pass from infected pregnant women to the fetus, resulting in abnormalities in two percent of cases. The fetus can develop scars on the skin and limb(s), limb deformities (hypoplesia), eye damage, low birth weight, brain atrophy (loss of neurons) and mental retardation. The virus sometimes leads to fetal death and/or spontaneous abortion. Some babies who got infected in the fetal stage die in infancy.

The Statistics
Before the varicella vaccine, the U.S. reported an estimated 4 million cases of disease a year, leading to approximately 11,000 hospitalizations and 100 deaths. Historically one out of every 10,000 cases of chickenpox proved fatal with 23 out of every 10,000 cases progressing to pneumonia. Since the chickenpox vaccine was licensed in 1995, the number of people who get chickenpox as well as hospitalizations and deaths from chickenpox each year has declined dramatically in the United States.

The Vaccine
The varicella vaccine protects against varicella, also known as chickenpox. The first dose is given to children between 12 and 15 months of age. The second dose is given between 4 and 6 years of age. The catch up schedule is followed for children who miss either or both of the doses. The measles, mumps, rubella, and varicella vaccine (MMRV) is also available.

All adults (without evidence of immunity to varicella) need 2 doses of varicella vaccine or a second dose if they have received only 1 dose. Pregnant women should be assessed for evidence of varicella immunity. Those who are not immune to varicella should receive the first dose of vaccine upon completion or termination of pregnancy and before discharge from the healthcare facility. The second dose should be administered 4–8 weeks after the first dose.

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