Chickenpox

What is chickenpox?

Chickenpox (varicella) is a highly contagious disease caused by the varicella zoster virus, a member of the herpesvirus family. It is usually a self-limited disease that lasts 4-5 days and is characterized by fever, malaise and a characteristic rash.

Who gets chickenpox?

Almost everyone gets chickenpox. In urban areas, 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 highly contagious. 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 infective.

What are the signs and 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 (vesicles) 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 exposure with a range of 11-21 days after exposure.

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

A person is usually able to transmit chickenpox from 1 to 2 days before the onset of the rash to six days after the appearance of the first lesion. Contagiousness may be prolonged in people with altered immunity.

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 syndrome has been a potentially serious complication associated with chickenpox. For this reason, children with chicken pox should not be treated with aspirin which may increase the risk of Reye syndrome. Newborn children (less than one month old) whose mothers are not immune, and patients with leukemia may suffer severe, prolonged or fatal chickenpox.

Is there a vaccine for chickenpox?

Yes, a chickenpox vaccine was licensed in the U.S. in 1995 and is recommended for children 12 to 18 months of age and older children who have not had chickenpox. Susceptible persons (those who have not had chickenpox or have not been vaccinated) 13 years of age and older at high risk for exposure should receive the chickenpox vaccine. High risk groups include teachers of young children, day care employees, residents and staff in institutional settings, college students, inmates and prison staff, military personnel, nonpregnant women of childbearing age, adolescents and adults living in households with children and international travelers. Recipients of the vaccine should not take aspirin for 6 weeks after the vaccination.

To protect persons with weakened immune systems following exposure, vaccine given within 3-5 days or a shot of varicella zoster immune globulin (VZIG) given within 96 hours, depending on the cause of lowered immunity, may be effective in modifying or preventing disease.

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 whom are susceptible. If a susceptible person is exposed, they should receive chickenpox vaccine.

Avoiding exposure of nonimmune newborns and patients with weakened immune systems to chickenpox is important.

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.