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Varicella (chicken pox) Vaccine


Routine immunization is the best protection against serious infections, including chickenpox. Learn about chickenpox and the chickenpox vaccine.

Vaccines (or needles) are the best way to protect against some very serious infections. The National Advisory Committee on Immunization (NACI) and the Canadian Paediatric Society recommend routine immunization against chickenpox.

About chickenpox

Chickenpox (varicella) is an illness caused by the varicella zoster virus. Symptoms include:

  • Blister-like rash
  • Itching
  • Slight fever
  • Fatigue

Chickenpox is very easy to catch:

  • It is spread through the air when someone who has the virus coughs or sneezes.
  • It can also be spread by touching a blister or the liquid from the blister.
  • Chickenpox is contagious 1 to 2 days before the rash begins and until all the blisters are crusted over.

Before widespread use of the chickenpox vaccine, there were about 350,000 new cases each year in Canada. Although the one-dose schedule of chickenpox vaccine has reduced disease and hospitalization, some children are still at risk of being infected after one dose. Two doses of chickenpox vaccine further protect against the disease and reduce hospitalizations and complications.

Chickenpox can cause problems such as:

  • Scarring of the skin
  • Skin or bone infections
  • Pneumonia

Serious illness, such as inflammation of the brain (encephalitis) can occur, but it is rare. Chickenpox can also be very dangerous for:

  • People with weak immune systems
  • Pregnant women, as the unborn baby may develop birth defects or serious complications.

In many people, the virus can become active again later in life and cause a painful rash called shingles.

Who should receive the vaccine

Children should receive 2 doses of chickenpox vaccine:

  • First dose at 15 months of age
  • Second dose at 4-6 years of age (it is usually combined (MMRV) with measles, mumps and rubella)

If a dose is missed, your healthcare provider will discuss the “catch-up” schedule with you.

Who should not receive the vaccine

Children should not get the vaccine if they have:

  • Allergies to the vaccine or any component of the vaccine
  • Previously experienced an allergic reaction to the varicella vaccine

Please consult with your healthcare provider if your child has:

  • A weakened immune system or takes medications that suppress the immune system
  • Received blood or blood products
  • A moderate to severe illness


As with most vaccines, side effects are usually mild and last for only a few days after getting the needle. Some common side effects include:

  • Redness
  • Swelling and tenderness in the area where the vaccine was given
  • Low grade fever

Some children might get a very mild chickenpox-like rash up to 26 days they get the vaccine. Severe reactions are rare.

Deciding not to vaccinate

The vaccine is required by law:

Your child will be at risk of getting chickenpox if you decide not to vaccinate.

Parents who choose not to vaccinate for personal choice must do the following:

Parents who choose not to vaccinate for medical reasons must do the following:

  • Have a doctor fill out a medical exemption form
  • Bring the form to the Halton Region Health Department

Need more information?

If you have more questions, speak to your healthcare provider or call the Health Department.