What is chickenpox?

Chickenpox, also called varicella, is an itchy rash illness caused by a virus.

What are the symptoms of chickenpox?

Rash is often the first sign of disease in children. Adults may have fatigue and fever one to two days before the rash. In unvaccinated individuals, the rash appears as red-raised spots that turn into itchy, fluid-filled vesicles. Fluid may drain from vesicles before they dry and crust. New crops of spots develop over several days, and spots in several stages of development are present at the same time.

Vaccinated individuals who develop chickenpox usually have mild symptoms with fewer than 50 spots (that rarely contain fluid), shorter duration of illness, and low or no fever.

What are the complications of chickenpox?

Complications of chickenpox include: 

• Skin and soft tissue infections
• Dehydration
• Pneumonia
• Encephalitis (inflammation of the brain)

Most healthy children and adults recover from chickenpox without additional health problems. 

Is there a treatment for chickenpox?

Healthcare providers may prescribe an antiviral medication to individuals at risk for more serious disease. If started within 24 hours of rash onset, antiviral medications may reduce the number of days over which new lesions appear, the duration of fever, and other symptoms.

Is there a vaccine for chickenpox?

Yes. Vaccination recommendations include the following:

• All adolescents 13 years of age and older and adults, especially non-pregnant women of childbearing age, who have never had chickenpox and have never been vaccinated, should get two doses 4 to 8 weeks apart.
• A second catch-up chickenpox dose is recommended for children, adolescents, and adults who previously had only one dose.
• Pregnant women who are not known to be immune should be vaccinated after their baby is born. Chickenpox vaccine should not be given to women during pregnancy.
• During a chickenpox outbreak, people who have only received one dose of vaccine should receive a second dose.

How effective is the chickenpox vaccine?

Studies have repeatedly shown that one dose of varicella vaccine is 70-90 percent effective in preventing chickenpox and 95 percent effective in preventing severe illness.  One study has investigated the effectiveness of two doses of the vaccine. Two doses were found to be 98 percent effective in preventing chickenpox and essentially 100 percent effective in preventing severe illness.

How is chickenpox spread?

Chickenpox spreads very easily from person to person by direct contact with fluid from blisters or through the air when someone with chickenpox coughs or sneezes.

The time period between exposure and the onset of illness is usually 14 to 16 days, but can range from 10 to 21 days.

Chickenpox is hard to recognize in those who have been vaccinated because the rash may be very mild. Vaccinated persons who get chickenpox are infectious to others and need to stay home while ill. .

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

• A person with chickenpox can spread the virus to others from 1 to 2 days before the rash appears until all blisters have formed scabs. This usually takes until 4 to 7 days after the rash appears.
• Vaccinated individuals who develop chickenpox are also considered infectious; however, most cases have fewer spots, which rarely contain fluid. These cases can spread the virus until all spots have faded or no new spots have developed within a 24-hour period, whichever is later.

What can be done to prevent the spread of chickenpox?

Wash hands often, avoid close contact with others who are ill and stay at home if ill.  Vaccination is the best way to prevent the spread of chickenpox.

For more information about chickenpox, please visit the Centers for Disease Control and Prevention or the Minnesota Department of Health.