Chickenpox is a highly contagious disease caused by the varicella virus, a member of the herpes virus family. It is the most commonly reported childhood disease. In 1994, there were 5,977 cases reported among New York City residents (rate of 81.6 cases per 100,000 persons). Effective in 1995, chickenpox is no longer required to be reported to the New York City Department of Health.
Chickenpox is transmitted to others by direct person-to-person contact, by droplet or airborne spread of discharges from an infected person's nose and throat, or indirectly through articles freshly soiled by discharges from an infected person's lesions. The scabs themselves are not considered infectious.
Initial symptoms include sudden onset of slight fever and feeling tired and weak. These are soon followed by an itchy blister-like rash. The blisters eventually dry, crust over, and form scabs. The blisters tend to be more common on covered than on exposed parts of the body. They may appear on the scalp, armpits, trunk, and even on the eyelids and in the month. Mild or inapparent infections occasionally occur in children. The disease is usually more serious in adults than in children.
Symptoms commonly appear 14-16 days after exposure, with a range of 10-21 days.
People with chicken pox are contagious from 2 days before the rash appears and until all lesions are crusted over or until no new lesions have appeared for 24 hours.
Chickenpox generally results in lifelong immunity. However, this infection may remain hidden and recur years later as Herpes zoster (shingles) in older adults and sometimes in children.
Reye's syndrome is a potentially serious complication associated with chickenpox. Newborn children (less than one month old) whose mothers are not immune and patients with leukemia may suffer severe, prolonged or fatal chickenpox. Immunodeficient patients and those on immunosuppressive drugs may have an increased risk of developing a severe form of shingles.
In 1992, acyclovir was approved by the U.S. Food and Drug Administration for treatment of chickenpox in healthy children. However, because chickenpox tends to be mild in healthy children, most physicians do not feel that it is necessary to prescribe acyclovir.
A vaccine to protect children against chickenpox was first licensed in March 1995.
Contact your doctor for further information about the chickenpox vaccine. Call 311 for help finding a doctor.
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Maintaining high levels of varicella immunization in the community is critical to controlling the spread of chickenpox. To prevent further spread of chickenpox, people infected with the disease should remain home and avoid exposing others who are susceptible. Infected persons should remain home until the blisters become dry and crusted. It is very important to avoid exposing non-immune newborns and persons with a weakened immune system to chickenpox.
Varicella vaccination is recommended for outbreak control. During an outbreak, persons who do not have adequate evidence of immunity should receive their first or second dose as appropriate.
In 2006, a new product called VariZIG became available to protect patients without evidence of immunity to varicella who are at high risk for severe disease and complications and have been exposed to chickenpox. The patient groups recommended to receive VariZIG include those with a weakened immune system, pregnant women who are not immune to varicella, newborns whose mothers have symptoms of varicella around the time of delivery (five days before to two days after delivery) and certain premature infants exposed to chickenpox as newborns.