Chickenpox (varicella zoster)

What is chickenpox?

Chickenpox is a highly communicable disease caused by the Varicella virus, a member of the herpes virus family. It is the most commonly reported childhood disease in New York State.

Who gets chickenpox?

Almost everyone gets chickenpox. In metropolitan communities, about 75 percent of the population has had chickenpox by age 15 and at least 90 percent by young adulthood. In temperate climates, chickenpox occurs most frequently in winter and early spring.

How is chickenpox spread?

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 the infected person's lesions. The scabs themselves are not considered infectious.

What are the symptoms of chickenpox?

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 mouth. Mild or inapparent infections occasionally occur in children. The disease is usually more serious in adults than in children.

How soon do symptoms appear?

Symptoms commonly appear 13-17 days after infection, with a range of 11-21 days.

When and for how long is a person able to spread chickenpox?

A person is able to transmit chickenpox from five days before onset of rash to not more than six days after the appearance of the first lesion. Contagion may be prolonged in people with altered immunity conditions.

Does past infection with chickenpox make a person immune?

Chickenpox generally results in lifelong immunity. However, this infection may remain hidden and recur years later as Herpes zoster (shingles) in a proportion of older adults and sometimes in children.

What are the complications associated with chickenpox?

Reye's syndrome has been a potentially serious complication associated with clinical 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.

Is there a vaccine for chickenpox?

A vaccine to protect children against chickenpox is still undergoing clinical trials. To protect high-risk newborns and immunodeficient patients from exposure, a shot of varicella zoster immune globulin (VZIG) is effective in modifying or preventing disease if given within 96 hours after exposure to a case of chickenpox.

What can a person or community do to prevent the spread of chickenpox?

The best method to prevent further spread of chickenpox is for people infected with the disease to remain home and avoid exposing others who are susceptible. If they develop symptoms, they should remain home until one week after the skin eruption began or until the lesions become dry. Pay particular attention to avoiding unnecessary exposure of nonimmune newborns and immunodeficient patients to chickenpox.