Chicken Pox

What is Chickenpox?

Chickenpox is a very common childhood illness that is spread very easily.  It is caused by the varicella zoster virus. It mostly affects children under the age of ten and over 90% of people are likely to have had chickenpox by the age of fifteen. Infection usually results in life-long immunity to chickenpox, however the virus may stay in the body and be re-activated later in life as shingles.

What are the symptoms?

The illness usually develops around 2-3 weeks after a child has been exposed to the virus. The first symptoms are much like a common cold and include fever, runny nose, cough, feeling generally unwell and a lack of energy. 

The chickenpox rash typically appears 1-2 days later. This begins as groups of small raised spots which occur all over the body, especially the face, chest and back. These spots form small blisters which then burst to leave open sores that begin to scab and heal over in the next 3-4 days. Complete recovery takes about 7-10 days.

For the vast majority of people it is a mild illness but more serious complications, such as pneumonia or bacterial skin infections, do occasionally occur. The illness is also more serious in newborn babies and for the unborn children of pregnant women who get chickenpox.

How is it spread?

During the early stages of the illness it is spread from one person to another by coughing and sneezing, but later it can be passed by direct contact with the open sores. People are infectious from a few days before the rash appears until all the sores have crusted over and dried, usually about a week after the rash first appears.

How is it treated?

Chickenpox does not usually require specific treatment. Because chickenpox is caused by a virus, antibiotics are of no use in treating the illness. However they may be prescribed if a patient develops a secondary bacterial infection.

It is important to try to prevent scratching the blisters as this may result in scarring or secondary bacterial infection. Luke-warm baths containing bicarbonate of soda (baking soda) or using other prescribed anti-itching medication may help relieve some of the itching. Drying should be done by patting down the skin with a clean, soft towel and not by rubbing. 

Paracetamol may be helpful in reducing pain and fever, but no medicines containing aspirin should be given to children as aspirin can increase the risk of serious complications.

Prevention

Measures to help prevent spread include:

• covering the mouth and nose when sneezing
• disposing of used tissues properly
• washing hands thoroughly after contact with sick people or used tissues
• not sharing eating utensils and cups
• staying away from work, school or preschool until all the sores have crusted over and dried.

Teachers and childcare centre operators should also be informed if a child attending has had this illness.

While most pregnant women are likely to have had chickenpox as a child and so not be at risk of getting it again, it is advisable for pregnant women to stay away from anyone suffering from chickenpox as chickenpox in the mother can harm the unborn child or be severe for a newborn baby. If a pregnant woman is exposed to someone with chickenpox or develops symptoms of chickenpox she should seek advice from her family doctor.

Immunisation

Chickenpox was added to the immunisation schedule as of July 2017. It is given as part of the 15 month immunisations. One dose of the vaccine will protect around four out of five people from any kind of chickenpox and almost everyone from severe chickenpox. Some people who have been vaccinated may still get chickenpox, but they will have a milder illness. Vaccination provides long term but probably not lifelong immunity to chickenpox.

• Immunise against chickenpox pamphlet - Health New Zealand | Te Whatu Ora

Shingles

Shingles is a condition caused by reactivation of the varicella zoster virus, and occurs in people who have previously had chickenpox.  After recovery from chickenpox the virus can remain inactive in the body to be reactivated at any time later in life and cause shingles. While shingles is caused by the same virus as chickenpox, it is not the same as chickenpox. It is mostly experienced by adults and is characterised a painful rash with blisters and sores, which may occur in a band on one side of the body or on the head. The rash may last 3 - 5 weeks, and the pain may continue even after the rash has disappeared.

The shingles rash is infectious and direct contact with the shingles rash can also result in chickenpox in those who have not previously had chickenpox. 

The shingles vaccine is part of the immunisation schedule and is given at age 65.  

Resources

• Chickenpox - Health New Zealand | Te Whatu Ora
• Chickenpox - Immunisation Advisory Centre