Immunizations - Hepatitis A

Varicella-Zoster Virus (Chickenpox)

Chickenpox (caused by the varicella-zoster virus) is one of the most contagious childhood diseases. Nearly every unvaccinated child becomes infected with it. The affected child or adult may develop hundreds of itchy, fluid-filled blisters that burst and form crusts.

The infection rarely causes complications in healthy children, but it is not always harmless. Five out of every 1,000 children are hospitalized and, in rare cases, it can be fatal. Before the vaccination became widespread, chickenpox resulted in about 11,000 hospitalizations and 100 deaths a year.

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Click the icon to see an x-ray of pneumonia following exposure to chickenpox.

Chickenpox can be especially severe in adults and very serious in anyone with a compromised immune system. In addition, the varicella virus (which persists in the body after the childhood disease is gone) erupts as a painful and distressing condition called herpes zoster (shingles) in about 20% of adults with a history of chickenpox. Chickenpox itself usually occurs only once, although a few cases of mild second infections, marked by the telltale rash, have been reported in older children years after their first infection.

Click the icon to see an image of the shingles.

Vaccines for Chickenpox

A live-virus vaccine (Varivax) produces persistent immunity against chickenpox. Data show that the vaccine can prevent chickenpox or reduce the severity of the illness even if it is used within 3 days, and possibly up to 5 days, after exposure to the infection.

Recommendations for the Vaccine in Children. The vaccine against chickenpox is now recommended in the U.S. for all children between the ages of 12 months and adolescence who have not yet had chickenpox. Children are given 2 doses of the vaccine. The first dose is recommended at age 12-15 months. The second dose should be given at 4 - 6 years. However, doses can be as little as 28 days apart (note that the ideal minimum time for children under 13 years is 3 months). To date, more than 75% of children have been vaccinated.