Chickenpox (Varicella)


What is Chickenpox?

Chickenpox is caused by the varicella-zoster virus. About 90 percent of chickenpox cases occur before the child becomes 12 years of age.  There is a vaccine.


What are the symptoms of Chickenpox?

Children with chickenpox will feel flu-like symptoms such as fatigue, mild headache, fever up to 39° C (102° F), chills and muscle or joint aches a day or two before the itchy, red rash appears. The rash appears anywhere on the body as raised red blisters that are extremely itchy. Some children have only a few blisters while others can have as many as 500. The child will be most infectious (contagious) from one to two days before the rash appears. These blisters dry up and form scabs in four to five days. In rare cases, chickenpox can cause other complications including pneumonia, and encephalitis. Complications of chickenpox tend to be more severe in adults and those with a weak immune system.


How do you get Chickenpox?

Chickenpox is extremely contagious, usually one to two days prior to the onset of the rash until all lesions are crusted (approximately 5 days). It spreads very quickly from person to person. The most common way the infection is spread is through the air if someone with chickenpox coughs or sneezes. You can also get chickenpox if you touch a blister or the liquid from a blister.


What about pregnant women and Chickenpox?

A pregnant woman with chickenpox can pass it on to her unborn baby before birth. Mothers with chickenpox can also give it to their newborn baby after birth.


Things you can do if someone is infected:

  • Notify the school/daycare.
  • Exclusion: A child with severe chickenpox and a fever should be excluded from school for five days after the rash begins or until all blisters have crusted. Children with a mild illness may return to school as soon as he/she is well enough to participate in normal activities (regardless of the state of the rash).  
  • Contact your doctor if you have concerns or especially if your child is very ill with a high fever lasting more than two days or if new spots continue to occur after the 7th day.
  • Encourage good personal hygiene. Anti-itch products will help soothe the itch. Keep fingernails cut short. Scratching the blisters may cause infection and scarring.
  • As noted above, a vaccine is now available for healthy persons over the age of one year that is effective to prevent chickenpox. Ask your health care provider if vaccination is right for you or your child.


This page provides basic information only. It must not take the place of medical advice, diagnosis or treatment. Always talk to a health care professional about any health concerns.

Source:  Ontario Ministry of Health and Long-Term Care, Public Health Division.


For Further Information

Call the Infectious Disease Program: (807) 625-5900

or toll-free 1-888-294-6630

Health Topic
Diseases & Infections