Chickenpox (Varicella zoster)

  • New York State Department of Health:

    Chickenpox (varicella zoster)

    Last Reviewed: November 2006

    What is chickenpox?

    Chickenpox is a highly communicable disease caused by the varicella virus, a member of the herpes virus family. In temperate climates, chickenpox occurs most frequently in winter and early spring.

    Who gets chickenpox?

    Chickenpox is common in the United States. Virtually everyone who is not vaccinated acquires chickenpox by adulthood. Cases are expected to decline as vaccine coverage levels increase.

    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 by contact with 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 unapparent infections occasionally occur in children. The disease is usually more serious in adults than in children.

    How soon do symptoms appear?

    Symptoms commonly appear 14-16 days (range of 10-21 days) after exposure to someone with chickenpox or herpes zoster (shingles).

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

    A person is most able to transmit chickenpox from one to two days before the onset of rash until all lesions have crusted. People who are immunocompromised may be contagious for a longer period of time.

    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 shingles in a proportion of older adults and sometimes in children.

    What are the complications 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. Immunocompromised patients, including those on immunosuppressive drugs, may have an increased risk of developing a severe form of chickenpox or shingles. Reye's Syndrome has been a potentially serious complication associated with clinical chickenpox involving those children who have been treated with aspirin. Aspirin or aspirin-containing products should never be given to a child with chickenpox.

    Is there a vaccine for chickenpox?

    A vaccine to protect children against chickenpox was first licensed in March 1995. It has been recommended for persons over 12 months of age. To protect high-risk newborns and immunocompromised 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. Older children and adults who have previously had chickenpox do not need to be vaccinated. Contact your doctor or local health department for further information about the chickenpox vaccine.

    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 and crusted. Pay particular attention to avoiding unnecessary exposure of nonimmune newborns and immunocompromised people to chickenpox.

    Is there a treatment for chickenpox?

    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.