Immunizations - Varicella-Zoster Virus (Chickenpox)

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Introduction	Hepatitis B	Smallpox
Diptheria, Tetanus, and Pertussis	Poliomyelitis	Other Vaccinations
Measles, Mumps, and Rubella	Pneumococcal Pneumonia	Resources
Varicella-Zoster Virus (Chickenpox)	Viral Influenza	References

Varicella-Zoster Virus (Chickenpox)

Chickenpox (caused by the varicella-zoster virus) isone of the classic childhood diseases, and one of the most contagious.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.

This is a close-up picture of chickenpox. Early chickenpox lesions consist of small red papules which quickly fill with a yellowish or straw colored fluid to form small blisters (vesicles), as seen in this photograph. Later, these vesicles will rupture forming shallow erosions that crust over and then ultimately heal.

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 after the childhood disease) 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.

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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 three days, and possibly up to five days, after exposure to the infection.

Recommendations for the Vaccine in Children. The vaccine against chickenpox is now recommended in the US for all children between the ages of 18 months and adolescence who have not yet had chickenpox. Children are given one dose of the vaccine. Two doses one to two months apart are given to people over 13 years of age. To date, more than 75% of children have been vaccinated.

Experts recommend that the chickenpox vaccine be given at the same time as the measles-mumps-rubella (MMR) vaccine or that there is a delay of at least a month between the two vaccinations. (If the chickenpox vaccination is given within that 30 day period--but not at the same time--there is a higher risk for a breakthrough infection later on.)