Chickenpox

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Did you know?

Chickenpox is usually a mild disease but it can be serious, especially in newborns, teenagers, adults, pregnant women, and those with weakened immune systems. 

Nathan's Story

Nathan's mom shares her story about the stroke Nathan suffered after becoming infected with chickenpox.

What is the chickenpox vaccine?

The chickenpox vaccine protects against chickenpox, a highly contagious disease caused by the varicella-zoster virus. 

Who should get the chickenpox vaccine? 

  • The chickenpox vaccine is given to children as a series of two doses. The first dose is given at 12 months of age and the second dose at 4 to 6 years of age. Children 4 - 12 years of age who also need protection against measles, mumps, or rubella can get their second dose of the chickenpox vaccine as the combined Measles, Mumps, Rubella, and Varicella (MMRV) vaccine.  
  • Students in Grade 6 who have not had two doses of the vaccine should also get the vaccine. Most grade 6 students would have had 1 dose of the vaccine on or just after their 1st birthday and will only need 1 more dose of vaccine. Grade 6 students who have never had the vaccine should get 2 doses.
  • The vaccine is also available as a series of 2 doses to people 13 years of age or older who have not been immunized against chickenpox.
  • People who had chickenpox before their 1st birthday should still get the vaccine. This is because they may not have developed a long-lasting immunity and could get chickenpox again.
  • People who had chickenpox or shingles disease at 1 year of age or older do not need to get the vaccine if:
    • They had the disease before 2004 or
    • The disease was confirmed by a lab test
  • The chickenpox vaccine is provided free as part of routine immunizations.
  • Although rare, some people may get chickenpox even after being immunized. The illness will be much milder than if they had not been immunized.

What are the benefits of the chickenpox vaccine?

The chickenpox vaccine is the best way to protect against chickenpox and its complications. When you or your child get vaccinated, you help protect others too. 

What are the side effects?

Vaccines are very safe. It is much safer to get the vaccine than to get chickenpox.

Many people have no side effects from the vaccine. However, for those that do, common side effects may include soreness, redness, and swelling where the vaccine was given. A mild fever and a rash, which looks like chickenpox but with fewer spots, can occur about 2 weeks after the vaccine.

Very rarely, a person who develops a rash after being immunized can spread the virus from the chickenpox vaccine. To prevent spreading it to others, cover the rash until the blisters have dried and crusted over.

It is important to stay in the clinic for 15 minutes after getting any vaccine because there is a very rare possibility, between one in 100,000 and one in a million, of a life-threatening allergic reaction called anaphylaxis. This may include hives, difficulty breathing, or swelling of the throat, tongue or lips. Should this reaction occur, your health care provider is prepared to treat it. Emergency treatment includes administration of epinephrine (adrenaline) and transfer by ambulance to the nearest emergency department. If symptoms develop after you leave the clinic, call 9-1-1 or the local emergency number.

It is important to always report serious or unexpected reactions to your health care provider.

Where can I learn more?

About chickenpox

  • Chickenpox (varicella) is an infection caused by the varicella-zoster virus.
  • Chickenpox is spread through the air when an infected person sneezes or coughs. It can also be spread through contact with the fluid from chickenpox blisters, or the saliva (spit) of a person who has chickenpox. A pregnant woman with chickenpox can pass it to her baby before birth.
  • Children with chickenpox have an average of 350 red, itchy blisters.
  • Infection in newborns, teenagers, adults, pregnant women, and those with weakened immune systems is more severe.
  • Complications from chickenpox include pneumonia (an infection of the lungs), encephalitis (swelling of the brain), and bacterial infections of the skin. Encephalitis can lead to seizures, deafness or brain damage.
  • About 1 in 3,000 adults will die from chickenpox.
  • Rarely, infection early in pregnancy can result in a baby being born with birth defects. This is known as congenital varicella syndrome. Chickenpox can also cause miscarriage or stillbirth.
  • For some people, the virus can become active again later in life and cause a painful rash called shingles. For more information on shingles, visit our shingles page
Date last updated: 
Thursday, Apr 09, 2020
Date last reviewed: 
Monday, Apr 06, 2020