University Health Service

Chickenpox (varicella) is a very contagious illness. Children and adults can get this viral infection if they haven’t had chickenpox in the past, or if they have not received two doses of the chickenpox vaccine.

Cause: Chickenpox is caused by the varicella virus.

Symptoms:

  • Initially, a person may have fever, tiredness, loss of appetite and headache, which can last 1-2 days.
  • People then develop a rash that turns into itchy, fluid-filled blisters, then the blisters turn into scabs. This process typically last 5-7 days. The rash usually develops 10-21 days after exposure (average 14-16 days).  
  • See photos of people with symptoms.

If you have symptoms, it's important that you contact your health care provider. U-M students and other UHS patients can call UHS Nurse Advice.

Transmission:  The virus can be spread from person to person by direct contact and also by breathing airborne particles. A person with chickenpox is typically contagious for 1-2 days before the rash begins, and until all of the blisters have crusted/scabbed.

Prevention:  If you have chickenpox, please protect others by staying home until all of the blisters have scabbed.

Vaccination is effective at preventing chickenpox. Two doses of vaccine are recommended for children age 1 year and older and also for adults, if they have not had the disease. The UHS Allergy, Immunization and Travel Health Clinic provides vaccination for a fee.  Pregnant women should not receive the chickenpox vaccine.

Two doses of vaccine are 98% effective at preventing chickenpox and 100% effective at preventing severe chickenpox.

Chickenpox can cause serious complications in newborns, people with an immune deficiency or cancer, and those who take systemic steroids. These individuals should avoid people who have chickenpox.

If you may have been exposed, call a health care provider if you have:

  • Never had the chickenpox disease or received 2 doses of the chickenpox vaccine
  • Are pregnant
  • Have a weakened immune system caused by disease or medication

Treatment: Treatment depends on the age of the individual and whether they are at risk of complications. Please consult your health care provider. U-M students may call UHS for Nurse Advice.  See also treatment information from the Centers for Disease Control and Prevention.

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