Facts about chickenpox

What is chickenpox?

Chickenpox (varicella) is a very common childhood infection caused by the varicella-zoster virus. It is most common in children and is usually mild. When adults get it, however, they can get very sick.

Chickenpox is dangerous for people with immune system problems, such as leukemia, or for people who are taking drugs that weaken the immune system, such as steroids.

What are the symptoms of chickenpox?

Chickenpox begins with a fever, followed in a day or two by a rash that can be very itchy. The rash starts with red spots that soon turn into fluid-filled blisters. Some people have only a few blisters; others can have as many as 500. These blisters dry up and form scabs in 4 or 5 days.

How is it spread?

Chickenpox spreads easily. It is most contagious on the day before the rash appears.

• It spreads from person to person through direct contact with the virus. You can get chickenpox if you touch a blister or the liquid from a blister. You can also get chickenpox if you touch the saliva of a person who has chickenpox. The virus enters the body by the nose or mouth and can make you sick, too.

• It can also be spread to you through the air if you are near someone with chickenpox who is coughing or sneezing.

• A pregnant woman with chickenpox can pass it on to her baby before birth.

• Mothers with chickenpox can also give it to their newborn babies after birth.

The only way to stop the spread of the virus from person to person is to prevent infected people from sharing the same room or house with healthy people, which isn’t a practical solution. Chickenpox cannot be spread through indirect contact.

Is there a vaccine against chickenpox?

Yes. The Canadian Paediatric Society (CPS) and the National Advisory Committee on Immunization recommend that all healthy children 12 months of age and older get the chickenpox vaccine. The CPS has an information sheet on the chickenpox vaccine available at <www.caringforkids.cps.ca/immunization/GettingyourShots.htm>.

What is shingles?

Shingles (zoster) looks like chickenpox and is caused by the same virus. However, it usually appears on only one part of the body. Shingles occurs in people who have already had chickenpox, usually many years later.

Shingles is very contagious. You can catch chickenpox from someone with shingles through contact with their secretions or their skin rash. You cannot get shingles from someone with chickenpox.

Can you catch chickenpox again once you have had it?

In most cases, getting chickenpox once means you will not get it again. This is called lifelong immunity. However, in rare cases, a person gets it again.

What can parents do to protect their children from chickenpox?

The best way to protect children from chickenpox is to have them vaccinated.

If your child is not yet vaccinated and comes in contact with another child who has chickenpox, he may still be protected if he is vaccinated right away.

If one of your children has chickenpox, it will probably spread to other members of the household who are not already immune. If someone else catches the infection, it will appear two to three weeks after the first family member got it.

If your child has an immune system disorder, contact your doctor. The doctor can give the child a special type of immune globulin (ie, varicella-zoster immune globulin), which contains a large number of antibodies (protective substances in the blood), to help prevent infection, or he can provide early treatment with an antiviral drug.

How can chickenpox be treated?

If your child gets chickenpox, do not give him aspirin (acetylsalicylic acid) or any products that contain aspirin. Taking aspirin increases the risk of getting Reye’s syndrome. This severe illness can damage the liver and brain. If you want to control your child’s fever, use acetaminophen (eg, Tylenol, Tempra and Panadol).

Taking good care of the skin and not scratching it may prevent infections that can be caused by bacteria that get into the skin. Your doctor may recommend a medication to help reduce the itch.

Can children with chickenpox go to child care or school?

If your child is too sick to take part in regular activities, or if he has a fever, he should stay home. For mild cases, children can go to child care or school as long as they feel well enough to participate in their activities. For more information about exclusion policies, see “Chickenpox: When should children stay at home?” (<www.caringforkids.cps.ca/immunization/ChickenpoxStayHome.htm>).

What if I’m pregnant?

Pregnant women can develop severe chickenpox. Most adult women are already protected against chickenpox by antibodies in their blood. If you are thinking of getting pregnant and have not had chickenpox, ask your doctor about whether you can be vaccinated.

If you are pregnant and have not had chickenpox, or if you have not lived in the same house with someone who has had chickenpox or shingles, call your doctor right away if you are exposed to chickenpox. Your doctor may want to give you an injection of varicella-zoster immune globulin to help prevent you from getting a severe infection.

If you catch chickenpox early in your pregnancy, there is a very small chance of it harming your unborn baby.

For more information

For complete information on vaccinations in Canada, read Your Child’s Best Shot: A Parent’s Guide to Vaccination, 2nd edition, a 344-page book produced by the CPS in 2002.