Chickenpox
Chickenpox is an acute and highly contagious viral infection caused by the varicella-zoster virus.
It is sometimes called varicella.
How it spreads
The virus may be transmitted by person-to-person contact via:
- droplet or airborne spread of respiratory secretions
- articles infected with the respiratory secretions
- blister fluid of an infected person.
Symptoms
The first symptoms generally develop between 2 to 3 weeks, with the average being 14 to 16 days, after the person is exposed.
Chickenpox begins with fever, fatigue and loss of appetite followed by a generalised rash a day or so later.
The rash is more concentrated over the trunk, face and scalp and starts as itchy red spots but rapidly progresses to blisters.
The blisters last 3 to 4 days before turning into scabs and drying out.
Several crops of blisters will appear over a period of days, resulting in various stages of development present on the body at any one time.
Healthy adults and children generally recover within 10 days.
Infectious period
A person is infectious from 2 days prior to onset of the rash until the blisters have all crusted into scabs, usually about 5 days after they appear.
Treatment
Most people do not require medical intervention. Rest and fluids are encouraged.
Reducing the risk of skin infection by scratching can be helped by:
- the use of over the counter anti-itch soaps and lotions
- keeping fingernails short.
Paracetamol can be used to reduce fever. Aspirin must not be given to young children and adolescents due to the risk of developing Reyes Syndrome.
Specific antiviral medication is available for chickenpox. However, it is reserved for those with severe disease or at risk for severe disease. A doctor’s prescription is required.
Control measures
People with chickenpox should not attend child care, preschool, school or work:
- until fully recovered or
- for at least 5 days after the rash first appears or longer if blisters are still present.
Once all remaining blisters have become scabs, exclusion is no longer required.
Encourage coughing or sneezing into the inner elbow rather than the hand and if tissues are used, put them in the bin straight away.
Hands should be thoroughly washed after handling tissues, contact with an infected person or after blowing or wiping the noses of affected children.
Towels, food, drinks and eating utensils should not be shared while people remain infectious.
Prevention
To prevent Chickenpox, a vaccine is available.
Since 2005, the vaccine has been free in Australia for children from 18 months to 13 years old.
One dose of the vaccine given to children in these age groups will prevent disease in up to 85% of cases.
Since the vaccine program started, there has been a decrease in children aged 1 to 4 years hospitalised with chickenpox.
Children who are not eligible for the free vaccine can purchase the vaccine privately with a doctor’s prescription.
Vaccination is also recommended for some people who may not have previously had chickenpox.
They include:
- health care workers
- teachers
- child-care workers
- household contacts of immunosuppressed persons
- women prior to pregnancy.
If the person receiving the vaccine is over 14 years of age, 2 doses of vaccine are required.
It is safe to have the vaccine even if you may have previously had chickenpox or the vaccine, or if you're unsure.
The vaccine is contra-indicated in pregnant women and immunosuppressed people.
If you are not immune and have been exposed
You can have the vaccine preferably within 3 days, and up to 5 days after exposure to prevent or modify the severity of disease.
Those at high risk of complications from infection with varicellazoster virus should seek medical advice if they have been exposed to chickenpox or shingles.
This includes people with leukaemia, young babies or pregnant women.
Administering zoster immunoglobulin (ZIG) to this group is effective in preventing or reducing the severity of chickenpox if given within 96 hours of exposure.
Information for health professionals
To find out more, go to the NT Health website.
Contact
Contact your nearest Centre for Disease Control on the NT Health website.