Chickenpox - immunisation

Chickenpox (caused by the varicella-zoster virus) is a highly infectious disease that usually causes an itchy red rash with blisters. It is one of the most common childhood diseases and can affect adults as well. Most people recover fully from chickenpox, but it can cause complications in children with lowered immunity and in some adults. A child with chickenpox can miss up to two weeks of school.

Immunisation with the chickenpox vaccine can protect your child from developing the chickenpox illness and possible serious medical complications.

Serious side effects or allergic reactions to the vaccine are rare. If you are concerned about your reaction or your child’s reaction to any vaccine, see your doctor immediately.

Immunisation can protect against complications

Most people recover fully from a dose of chickenpox with no ongoing problems, but it can cause complications – especially in people with lowered immunity and in some adults. These may include:

• More severe symptoms in adults
• Shingles (herpes zoster)
• Bacterial skin infections resulting in scarring, pneumonia (lung infection) or inflammation of the brain
• Risks to the unborn baby – including malformations, skin scarring and other problems – if the mother contracts chickenpox infection in the first half of the pregnancy
• Serious illness or death in all ages.

Immunisation can prevent serious medical problems. For children who have not had chickenpox, the vaccine can help protect them against serious complications associated with the chickenpox illness and from developing shingles in later life. Immunised children who do get chickenpox generally have a much milder form of the disease. They have fewer skin lesions, a lower fever and recover more quickly.

The chickenpox vaccine

The chickenpox vaccine is provided free of charge to babies and some children in Australia under the National Immunisation Schedule. The age range for eligible children varies between States and Territories.

In Victoria, the free vaccine is available to:

• All babies – at 18 months of age if there is no history of chickenpox
• Catch-up – single dose from 19 months to seven years of age (inclusive)
• Year 7 secondary school students – as a ‘catch-up’ immunisation, if they have not had chickenpox or received the vaccine.

Other people wishing to have the vaccine can purchase it with a prescription. Your immunisation provider can provide more information.

How the vaccine works

The chickenpox vaccine is used in children aged from 12 months or older, adolescents and adults. It contains a weakened form of the chickenpox (varicella-zoster) virus and works by causing the body to reproduce its own antibodies to protect against the disease.

A doctor or nurse will inject the vaccine under the skin of the upper arm or thigh – it should never be given intravenously (directly into the vein). Children are given the vaccine as a single dose. Adults and adolescents aged 14 years and older are generally given two doses, one to two months apart.

People who should be immunised

People who benefit most from immunisation include:

• Infants and children
• Adults not immune to chickenpox, especially parents with young children and people in ‘at-risk’ occupations such as teachers, childcare workers and health care workers
• Adults and young children who are not immune and live with people who have lowered immunity and have no history of chickenpox.

Children and adults who are known to have had chickenpox are considered to be immune.

Some people should not be immunised

The chickenpox vaccine should not be given if:

• You or your child has an allergic reaction to the vaccine or any ingredients contained in the vaccine
• You are, or think you may be, pregnant or intend to become pregnant within one month of immunisation
• You or your child has lowered immunity due to immune deficiency, abnormal blood conditions or disorders, cancer, HIV or certain medications
• You or your child has a severe infection with a high temperature
• You have had another live virus-containing vaccine within the last month, such as a vaccine for measles, mumps or rubella.

Before immunisation

Before receiving the vaccine, tell your doctor or nurse if you or your child:

• Is unwell
• Has allergies to any other medicines or substances
• Has received another vaccine within the last month or is to have another vaccine within one month of the chickenpox immunisation
• Has received a blood or plasma transfusion or immunoglobulins within the last three to nine months or will need to receive them within three weeks of the chickenpox immunisation
• Is taking any prescription or over-the-counter medicines
• Is to have a skin test for tuberculosis within four to six weeks of receiving the chickenpox vaccine
• If you intend to become, or are, pregnant.

Possible side effects of the vaccine

All vaccines and medicines can have side effects. However, these are usually not serious. Side effects from the chickenpox vaccine may include:

• Redness, swelling or soreness at the injection site
• High fever (over 39°C)
• Mild chickenpox-like rash – this may develop five to 26 days after the immunisation. It is important to avoid contact with people who have low immunity while the rash lasts
• A very mild dose of chickenpox a year after receiving the vaccine – this side effect is uncommon and occurs because the vaccine is not fully effective in every person.

There is a very small risk of a serious allergic reaction to any vaccine. Signs of an allergic reaction may include an itchy rash, shortness of breath and swelling of the face and tongue. It is important to stay at the clinic where the immunisation was given for 15 minutes after the immunisation.

Reducing the side effects

Side effects of the vaccine can be reduced by:

• Drinking extra fluids
• Not overdressing
• Applying a cold, wet cloth over the sore injection site
• Taking paracetamol to reduce fever – check the label for the correct dose (especially for children).

If you are concerned about your reaction or your child’s reaction, see your doctor immediately.

Where to get help

• Your doctor
• Your local government immunisation service
• Maternal and child health nurse
• NURSE-ON-CALL Tel. 1300 60 60 24 – for expert health information and advice (24 hours, 7 days)
• Immunisation Program, Department of Health Victoria Tel. 1300 882 008
• National Immunisation Infoline Tel. 1800 671 811

Things to remember

• Chickenpox is a highly infectious disease that sometimes causes complications.
• The chickenpox vaccine is of greatest benefit to children over 12 months and people who live with someone with lowered immunity.
• Serious side effects or allergic reactions to the vaccine are rare and should be attended to immediately by your doctor or at the nearest hospital.

You might also be interested in:

• Chickenpox.
  
• Diphtheria.
  
• Immune system.
  
• Immunisation - childhood.
  
• Immunisation - facts and misconceptions.
  
• Measles.
  
• Mumps.
  
• Rubella.
  
• Shingles.
  
• Tetanus.
  
• Vaccines.
  
• Whooping cough.
  

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Department of Health

Fact sheet currently being reviewed.
Last reviewed: February 2010

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Chickenpox (varicella) is a highly infectious disease that causes an itchy red rash with blisters. Immunisation with the chickenpox vaccine can protect your child from developing the illness and possible serious medical problems. Serious side effects or allergic reactions to the vaccine are rare.

Content on this website is provided for education and information purposes only. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your qualified health professional. Content has been prepared for Victorian residence and wider Australian audiences, and was accurate at the time of publication. Readers should note that over time currency and completeness of the information may change. All users are urged to always seek advice from a qualified health care professional for diagnosis and answers to their medical questions.

For the latest updates and more information, visit www.betterhealth.vic.gov.au

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