Chickenpox – immunization

Chickenpox is caused by the varicella-zoster virus (VZV). It is a highly infectious disease that usually causes an itchy red rash with blisters. It is most common in childhood, but it can affect adults as well.

Most people recover fully from chickenpox without lasting problems, but it can cause complications. A child with chickenpox can miss up to two weeks of school.

Immunization can prevent serious complications#

For children who have not had chickenpox, the vaccine can help protect them against the serious complications of the disease and reduce their risk of developing shingles later in life. Immunized children who still catch chickenpox (known as breakthrough chickenpox) generally have a much milder illness. They tend to have fewer skin lesions, a lower fever and a quicker recovery.

Research shows that two doses of the chickenpox vaccine in children provide stronger protection and reduce the chance of chickenpox occurring later. Vaccination schedules vary from country to country, so check with your doctor or immunization provider about the doses recommended where you live and when they are due.

In many programs, protection against chickenpox is given as a combined vaccine that also covers measles, mumps and rubella (MMRV). Children who have already had chickenpox can still receive the combination vaccine.

Who benefits most#

People who benefit most from being immunized against chickenpox include those who are not already immune – that is, people who have neither been immunized nor had the disease. This includes:

• adults who are not immune, especially parents of young children
• people in occupations with higher exposure, such as teachers, childcare workers and healthcare workers
• young children who are not immune
• people who live with someone who has a weakened immune system

If you are not immune, your healthcare professional can confirm this with a blood test, and you can arrange to receive the vaccine. Older children and adults are generally recommended to have two doses of the chickenpox vaccine given one to two months apart, while the youngest children may receive the combined MMRV vaccine.

Chickenpox and pregnancy#

The chickenpox and MMRV vaccines contain a very weakened form of the virus that prompts the body to make its own protective antibodies. Because of this, they are not given during pregnancy.

If you are not immune and not pregnant, you may decide to be vaccinated before you become pregnant. If you are not immune during pregnancy, avoid contact with anyone who has chickenpox. Contact your doctor, midwife or hospital as soon as possible if you are exposed to someone with the infection.

Before being vaccinated#

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

• are unwell or have a fever
• have allergies, or have had a serious reaction to a vaccine or any of its components
• have a condition or are having treatment that lowers immunity
• are taking any prescription or over-the-counter medicines
• have received, or will soon receive, another vaccine within about a month of the chickenpox vaccine
• have had, or will soon need, a blood or plasma transfusion or immunoglobulins
• are pregnant or intend to become pregnant

Side effects#

The chickenpox vaccine is effective and safe, but, like all medicines, it can have unwanted side effects. Most are mild and temporary, occurring in the first few days after immunization. They can include:

• pain, redness and swelling at the injection site
• occasionally, an injection-site lump that may last several weeks and needs no treatment
• a mild chickenpox-like rash, usually near the injection site but sometimes elsewhere, appearing a few days to a few weeks after the vaccine
• fever

If a fever is present, it can be managed by drinking extra fluids and not overdressing. Paracetamol may be used if needed – check the label for the correct dose or ask your pharmacist. Routine use of paracetamol after immunization is not recommended.

If a side effect is unexpected, persistent or severe, or if you are worried about yourself or your child after immunization, see your doctor or immunization nurse promptly, or go directly to a hospital. It is important to seek advice if you are unwell, as this may be due to another illness rather than the vaccine.

There is a very small risk of a serious allergic reaction (anaphylaxis) to any vaccine. For this reason, you are usually advised to stay at the clinic for at least 15 minutes after immunization in case further treatment is needed. Another rare side effect is thrombocytopenia, a bleeding problem caused by too few blood platelets. If you experience a serious or unexpected reaction, ask your immunization provider how to report it.

Deciding which immunizations you need#

The immunizations you may need depend on your health, age, lifestyle and occupation. Talk to your doctor or immunization provider if you think you or someone in your care has factors that could make vaccination important.

Key points#

• Chickenpox is caused by the varicella-zoster virus (VZV).
• It is a highly infectious disease that usually causes an itchy red rash with blisters.
• It is most common in childhood, but it can affect adults as well.
• Most people recover fully, but chickenpox can cause complications.
• Immunization can prevent serious complications.

Where to get help#