Varicella (chickenpox) vaccination program - common questions & answers for providers
State and Territory information:
Questions and answers about varicella vaccine eligibility, herpes zoster, reporting to the Australian Childhood Immunisation Register (ACIR), and impact on payments under the General Practice Immunisation Incentives (GPII) Scheme.
Who is eligible for free varicella vaccine?
Why is varicella vaccine provided to these age groups?
What are the possible consequences of varicella infection?
Which vaccines will be used in the National Varicella (Chickenpox) Vaccination Program?
How effective is the vaccine and what is its impact on the incidence of herpes zoster (shingles)?
What if the child has already had varicella?
Should varicella vaccinations be reported to the Australian Childhood Immunisation Register (ACIR)?
Do these changes to the National Immunisation Program affect payments under the General Practice Immunisation Incentives (GPII) Scheme?
More information
Who is eligible for free varicella vaccine?
All children born on or after 1 May 2004 at 18 months of age.A one year cohort of children aged between 10 and 13 years who have not received varicella vaccine and who have not had the disease are also eligible - the commencement date and the specific age group selected will vary between the States and Territories.
Why is varicella vaccine provided to these age groups?
Vaccination is recommended at 18 months of age due to evidence that the vaccine is more effective at this age than if given to younger children. It is also important that varicella vaccine is not given within four weeks of the first measles-mumps-rubella (MMR) dose due at 12 months of age, as this may result in the vaccines not being effective. Children vaccinated against varicella before 12 months of age require a second dose of vaccine at 18 months of age.Varicella vaccination is recommended for children aged between 10 and 13 years who have not received varicella vaccine and who have not had the disease. This is because the severity of varicella infection is greater in adolescents and adults. For example, while adults experience only about 25% of varicella cases, they account for 40% of all hospital admissions for varicella in Australia. The range of 10 to 13 years is optimal to ensure immunity before this higher risk age and because only one dose of vaccine is required (two doses are required for those aged 14 years or older).
These recommendations are endorsed by the National Health and Medical Research Council and published in the Australian Immunisation Handbook 2003 8th Edition.
What are the possible consequences of varicella infection?
Varicella is usually a mild disease of short duration in healthy children. It is more severe in adults and can cause serious and even fatal illness in immunosuppressed people of any age. Acute varicella may be complicated by cerebellar ataxia, aseptic meningitis, transverse myelitis, thrombocytopenia, encephalitis and pneumonia.Congenital varicella syndrome has been reported after varicella infection in the first half of pregnancy and may result in congenital malformations, skin scarring, and other abnormalities.
In an unimmunised population, about 75% of children will have had varicella by the age of 12 years. Approximately 5% of cases are subclinical. There are about 240,000 cases, 1500 hospitalisations and seven deaths from varicella each year in Australia.
Herpes zoster (shingles) is a localised vesicular rash resulting from reactivation of latent varicella-zoster virus in a period of waning immunity. Herpes zoster is often a serious illness in older adults and immunocompromised individuals, and some may develop disseminated zoster with visceral, central nervous system and pulmonary involvement.
Which vaccines will be used in the National Varicella (Chickenpox) Vaccination Program?
There are two varicella vaccines licensed for use in Australia :- Varilrix ( GlaxoSmithKline); and
- Varivax Refrigerated (CSL/Merck Sharp & Dohme).
How effective is the vaccine and what is its impact on the incidence of herpes zoster (shingles)?
Seroconversion occurs in 90 to 100% of those vaccinated. Breakthrough infection after exposure occurs at a rate of 1 to 2% a year in those vaccinated, however these infections are usually mild.It is extremely rare for the vaccine strain of the virus to reactivate in vaccine recipients and cause herpes zoster (shingles). Therefore, in vaccine recipients, the incidence of herpes zoster is likely to be lower over time compared with those infected naturally with varicella.
What if the child has already had varicella?
Clinical judgement should be used in this instance. A parental history of a child having had varicella is strongly predictive of immunity to varicella. However, it is safe to give varicella vaccine even if a child has had the disease, as the vaccine is well tolerated by those who are already immune to varicella. If a parent is unsure about whether their child has had varicella, it is recommended that they be vaccinated.If you are certain the child has had varicella and do not wish to vaccinate, you should notify the Australian Childhood Immunisation Register of this natural immunity, in writing on your letterhead. It is important to do this in order to maintain a complete record for the child.
Should varicella vaccinations be reported to the Australian Childhood Immunisation Register (ACIR)?
All vaccines administered to children less than seven years of age should be notified to the ACIR, in order to maintain a complete immunisation history for the child on the register. There will now be a notification payment for the 18 month schedule point associated with varicella vaccination reported to the ACIR.Initially, varicella vaccination will not be linked to eligibility for Maternity Immunisation Allowance and Child Care Benefit. Linkage may be reviewed after the program is established.
Do these changes to the National Immunisation Program affect payments under the General Practice Immunisation Incentives (GPII) Scheme?
A GPII Service Incentive Payment (SIP) will be paid for a varicella vaccination administered at 18 months and reported to the ACIR.At this point in time, varicella vaccination is not included in the assessment of immunisation status in the calculation of GPII practice outcomes payments. The inclusion of varicella vaccination may be considered at a later date.
More information
Information about the General Practice Immunisation Incentives (GPII) Scheme is available on the Medicare Australia website, or phone 1800 246 101 (free call - 24 hours).Information about the Australian Childhood Immunisation Register (ACIR) is available on the Medicare Australia website or phone 1800 653 809 (free call).
For technical information refer to Part 3.27 Varicella-Zoster of the Australian Immunisation Handbook 9th Edition 2008 (NHMRC).
Page last modified: 08 April, 2008