What you need to know about varicella (chickenpox)

About varicella (chickenpox)...

What is chickenpox?

Chickenpox or varicella is a common, highly contagious infection that is caused by the varicella-zoster virus.

What are the symptoms of chickenpox?

Chickenpox begins with a low fever, runny nose and sore muscles.  A day or two later, an itchy rash appears that soon turns into blisters filled with fluid. Children with chickenpox can become covered with hundreds of these itchy, sore blisters, mostly on their face, scalp and chest.  If the blisters get infected, they can turn into permanent scars.  After about 5 days, the blisters dry out and become crusted.  Altogether, chickenpox lasts between 7-10 days.

How can my child catch chickenpox?

The varicella virus spreads very easily.  If children are near an infected person who coughs or sneezes, there is a strong possibility that they will get chickenpox.  The infection also spreads when children touch someone's chickenpox blisters and then rub their eyes or mouth. An unborn baby can get chickenpox from a pregnant mother who has the infection. The best way to stop the virus from spreading is to stay away from people with chickenpox; however, this is not always possible when the infection is in a family.

Why is chickenpox serious?

In some children, chickenpox causes severe skin infections, including flesh-eating disease in rare cases.  Children with chickenpox can get pneumonia, scars (if blisters get infected) and even encephalitis, which is swelling of the brain.  For babies exposed before birth, there is a higher risk of birth defects, pneumonia, brain damage or death. Newborn babies, adults and those with compromised immune systems are in danger of having serious complications from chickenpox.

Why should my child be immunized against chickenpox?

For most children, being immunized means that they will never get chickenpox.  For a few people, being immunized means that if they do get chickenpox, it will be very mild, and they will recover quickly. Children who are not immunized against chickenpox are at risk of becoming infected later on in life when there is a much higher risk of complications.

About the chickenpox vaccine...

What kind of vaccine is given to prevent chickenpox?

The chickenpox (varicella) vaccine is given by needle and is very safe.  It was authorized for use in Canada in 1998, and like all vaccines authorized for use in Canada , it went through several stages of rigorous testing before being authorized for use. The varicella vaccine can be administered in a separate dose, by itself. Alternatively, the varicella vaccine can also be administered as part of a combined vaccine called MMRV that also protects your child from mumps, measles and rubella.

Are there any side effects?

Side effects of the chickenpox or the MMRV vaccines are usually very mild.  Your child's arm may be a little bit sore where the needle went in.  A few children may have a mild fever, which lasts for a few days. Within 1-2 weeks of immunization, a small percentage of children (6%) may develop a rash that looks like a mild case of chickenpox. Overall, these side effects from the vaccines are much milder than any complications from a serious case of chickenpox.

When should my child get the chickenpox vaccine?

The chickenpox vaccine is recommended for all children aged 1-12, and is usually given after your child's first birthday.

Schedules may vary from province to province.  Calculate your child's personal immunization schedule to see when your child should be immunized against 13 vaccine preventable diseases, including chickenpox.

If I vaccinate my child from chickenpox vaccine using the MMRV vaccine, can giving my child several vaccines at the same time overwhelm the immune system?

No.   Combination vaccines that provide protection against multiple diseases in one vaccine have been shown to be safe and effective. Giving combination vaccines protects children against more diseases sooner. As added benefits, it reduces children's discomfort by reducing the number of injections they receive and it saves parents the time and expense of additional office visits.

Who should not get the chickenpox vaccine?

Canadian guidelines advise that the following groups of people should not get the chickenpox vaccine:

• People with a  history of severe allergic reaction to the vaccine or a component of it (including gelatin or neomycin) should not receive further doses
• babies less than one year old
• pregnant women, or those who are trying to get pregnant.

People with weakened immune systems should only get the chickenpox vaccine if they are supervised by an infectious disease specialist.

What should you do if you are pregnant and have been exposed to chickenpox?

Chickenpox can be a risk for pregnant women and for their unborn babies.

If you have had the chickenpox vaccine—or chickenpox—you are protected from this disease during your pregnancy.

If you have never had the vaccine or chickenpox, talk to your doctor about the risks during pregnancy.

If you are pregnant, and have never had the chickenpox vaccine or chickenpox and think you may have been exposed to the disease, call your doctor right away.  There is a special shot that may prevent you from getting chickenpox, but timing is important!  You must get this shot within four days of being exposed to the disease.

Related Information

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• More answers to your top vaccine questions
• Varicella (chickenpox) information for Health Professionals