What is chickenpox and why do we vaccinate against it?
Wednesday 21 February 2018
Many Queensland adults remember getting chickenpox as kids. For most, the effects of the virus weren’t so bad: a few days of an itchy rash, temperature, runny nose and headache, before everything cleared up and childhood continued as normal. But for some, chickenpox can be a dangerous, even deadly, disease. Read on to find out what chickenpox is and the important reasons we vaccinate against it.
What is chickenpox?
Chickenpox is a disease caused by the varicella-zoster virus. It is highly contagious, which means it spreads very easily between people. Children and adults of any age can get chickenpox, but it is more common in children.
For the majority of children, chickenpox is generally a mild, but uncomfortable illness. Chickenpox is usually much worse in adults. Infected people start feeling cold-like symptoms, including a mild fever, headache, runny nose and cough. A day or two later, a rash begins to spread across the body, starting with pink blotches that progress into itchy blisters. Three to four days later, the blisters usually begin to dry out and turn into scabs.
Why do we vaccinate against chickenpox?
Serious complications from chickenpox are rare, but they do happen, even in otherwise healthy children and adults. Life-threatening complications such as pneumonia or encephalitis (inflammation of the brain) can be caused by chickenpox.
Prior to the introduction of chickenpox vaccination in Australia, there were approximately 240,000 cases and 7 deaths each year from chickenpox. This is one reason why vaccination against chickenpox is recommended.
The risk of severe chickenpox and its complications is greater in adolescents and adults, or people with a suppressed immune system. However, the majority of hospitalisations still occur in otherwise healthy children less than 5 years of age.
If a person has a supressed immune system, as a result of an illness or the need to take medication, catching chickenpox can be serious, even fatal. These people may not be able to receive the vaccine themselves and they rely on people around them being vaccinated so that the virus is less likely to spread to them.
Chickenpox can also cause damage to an unborn baby if the mother catches the virus during pregnancy. If a woman develops chickenpox late in pregnancy or very soon after birth, the infection can be serious and even life threatening for the newborn baby. Widespread vaccination in the community can reduce the chance a pregnant woman will catch chickenpox and spread it to her baby.
Varicella zoster virus can also cause shingles in adults later in life. Shingles occurs when the virus, which stays in the body after a person has chickenpox, becomes active again. It can cause a painful rash across one side of the body, on the face, chest, back, abdomen or pelvis that lasts for a number of weeks. In some cases, shingles can cause Ramsay Hunt syndrome, which can cause facial paralysis and hearing loss. Vaccinating children against chickenpox can reduce their risk of developing shingles as adults.
How does vaccination work?
The chickenpox vaccine contains a weakened version of the chickenpox virus. After vaccination, the immune system makes the antibodies and memory cells needed to provide long-term protection against infection. If the body comes into contact with the real virus, the immune system is then better able to respond to the virus, either stopping the disease from developing or reducing the severity of the disease and the risk of serious complications.
The best way to prevent chickenpox is vaccination. The vaccine is very safe and effective at preventing disease. The chickenpox vaccine prevents almost all cases of severe disease.
In some instances, some people aren’t able to be vaccinated. They might have a suppressed immune system, which means vaccination could cause dangerous side effects. Some people can be allergic to the ingredients in vaccines. If you have concerns about your children being allergic to vaccines, you should talk to your GP and they can advise you how to best proceed. People who are unable to receive vaccines rely on the rest of the community to be vaccinated, so that the virus is less likely to spread to them.
What should I do if I’m not vaccinated or my children aren’t vaccinated?
Talk to your GP or immunisation provider as soon as possible about how to proceed with vaccinations. You don’t need to receive the vaccine if you’ve already had chickenpox, but it won’t harm you if you do get the vaccine.
The National Immunisation Program Schedule provides a combined measles, mumps, rubella and varicella (MMRV) vaccine free of charge to all children aged 18 months. Children who have previously had chickenpox can, and should, still receive MMRV vaccine.
Vaccination is also recommended (but not funded) for non-immune people in the following groups:
- non-immune adolescents over 14 years of age and adults (this requires two doses given at least four weeks apart to achieve adequate protection from chickenpox)
- high-risk occupations where exposure to chickenpox is likely (eg. healthcare workers, teachers, childcare staff)
- women planning a pregnancy (chickenpox vaccine should not be given during pregnancy nor should the recipient become pregnant for 28 days after vaccination)
- women immediately after delivery of a baby
- parents of young children
- and household contacts of people with suppressed immune systems.