Chickenpox (Varicella) Fact Sheet

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Chickenpoxis a highly contagious disease caused by a virus called varicella-zoster.

Chickenpox occurs most frequently in the winter and early spring.  Approximately 90% of chickenpox cases occur in children 1 to 14 years of age, and 90% of people have had chickenpox by their early 20’s.  The disease is usually mild, and not life threatening in otherwise healthy children, but can be more serious in newborn babies and adults.  A person usually has only one episode of chickenpox, but the virus can lie dormant within the body and resurface later in life causing shingles (herpes zoster). More severe but rare complications of chickenpox include pneumonia (lung infection), skin infection, blood infection, or brain involvement. 

Chickenpox is spread from person-to-person by airborne droplets and direct contact with infected secretions.

It is highly contagious and is spread by touching the blisters, saliva, or mucus of an infected person, or from virus spread through the air.  Chickenpox may also be spread by contact with articles freshly soiled by discharge from an infected person’s lesions.  People with chickenpox can spread the disease from 1 to 2 days before the rash develops until all the lesions are crusted over (approximately 5 days).  Anyone with chickenpox should not attend childcare, school, work, or other public places until the blisters are dry and crusted.

Symptoms to look for include:

  • Sudden onset of fever
  • Itchy blister-like rash

Symptoms can occur within 10 to 21 days (usually 14 to 16 days) after exposure to someone with chickenpox. Itchy blisters are usually most concentrated on the face, scalp, and upper trunk.

Laboratory testing is available to confirm chickenpox.

People who think they may have chickenpox should see a doctor or their local health department.  Chickenpox is often diagnosed by its symptoms; however blood tests or scrapings and fluid from the rash vesicules can help in confirming the diagnosis.

See a doctor for treatment.

Several options are available to help manage and treat chickenpox.  If given within 24 hours after the rash develops, some treatments may lessen the severity of the disease.  Treatment of chickenpox depends on many specific factors, so you should consult with your doctor or local health department for advice.  Always call your doctor’s office or local health department before visiting so that other patients can be protected if necessary.

A person in close contact with someone who has chickenpox may also need treatment.  People 12 months of age or older that have been exposed and are considered susceptible to catching chickenpox should receive chickenpox vaccine within 3 to 5 days of exposure.  Other prevention options are available for certain situations.  Consult with your doctor or local health department for advice.  High risk contacts may include:

  • Pregnant women because of the danger to the unborn baby;
  • A newborn baby whose mother develops chickenpox 5 days before to 2 days after delivery; or
  • People with weakened immune systems, such as people with cancer, organ transplant patients, and HIV.


Chickenpox can be prevented with chickenpox vaccine.

2 doses of chickenpox vaccine are recommended for all healthy children 12 months to 18 years of age.  Vaccine is also recommended for persons 19 years and older who have not had chickenpox and are at high risk for exposure such as those living in a household with children, teachers, institutional residential staff, healthcare workers, college students, or international travelers.  Age-appropriate vaccination against chickenpox is required for enrollment in Maryland childcare institutions and schools.  For additional information about chickenpox vaccine, please visit: