Australian Immunization Update
Jonathan Cohen, MD
The Australian Immunisation Handbook 8th edition was recently updated (Sept 2003) and endorsed by the National Health and Medical Research Committee (NHMRC) (http://immunise.health.gov.au/handbook.htm). Utilising an evidence-based approach, a number of changes have been made which affect Australians intending to travel overseas, inbound travellers intending to reside in Australia for longer periods, and travellers on their way to developing countries via Australia.
The Australian Standard Vaccination Schedule (ASVS) lists a number of vaccines routinely recommended by the NHMRC, some of which are funded under the National Immunisation Program (NIP). Changes to the ASVS are listed and there is also a new chapter specifically dedicated to overseas travel.
The main changes to the ASVS are:
- The 18 month dose of acellular diphtheria-tetanus-whooping cough vaccine DTPa (Infanrix) is no longer given.
- Conjugate pneumococcal vaccine 7vPCV (Prevnar) is recommended for all children at 2, 4 and 6 months of age. The vaccine is currently funded only for children under the age of 5 years with specified predisposing risk factors.
- Acellular diphtheria-tetanus-whooping cough vaccine dTpa (Boostrix) is given for 15 - 17 year olds.
- Varicella vaccine is recommended for all children at 18 months of age, with a catch up dose for adolescents 10 - 13 years without a history of infection or vaccination. This vaccine is not currently funded under the NIP.
- Inactivated polio vaccine (IPV) is recommended rather than oral polio vaccine (OPV), however, either is appropriate. IPV for paediatric use is expected to become available within a combination vaccine, but is not funded under the NIP as a separate vaccine.
Haemophilus Influenzae B (HiB) continues to be given routinely within the early paediatric schedule.
Universal vaccination for neonatal and adolescent groups is now routine in Australia.
Meningitis C is given at 12 months of age.
Measles-Mumps-Rubella (MMR, Priorix) continues to be recommended as a two dose regimen in the paediatric schedule. A one time booster dose is recommended for anyone born after 1966 (when measles vaccine was introduced into Australia) who does not have two documented doses of the vaccine or who has not been infected.
Influenza and Pneumonia vaccination continues to be recommended for at risk groups, with influenza vaccination to be considered for travel to the Northern Hemisphere winter season.
For overseas travel
DTpa is recommended for individuals between 8 - 50 year of age and ADT for over 50, if travelling to areas where health services may be difficult to access and more than 10 years have elapsed since their last dose of tetanus.
Whilst the 5th dose of polio is no longer recommended, a booster dose should be given to travellers to areas or countries where poliomyelitis is epidemic or endemic. This particularly applies to the Indian subcontinent, parts of Africa and the Middle East. Sabin OPV can be given but not as a primary series, or if the person or household contact is immunosuppressed, in which case IPV is recommended.
Hepatitis A is recommended to virtually all travellers to endemic areas, i.e. most developing countries. Screening for hepatitis A IgG may be cost effective for those born prior to 1950, if born overseas, or with a past history of unexplained jaundice.
Typhoid vaccination is only recommended for travellers at risk, i.e. travelling to endemic countries where hygiene is poor or drinking water is unsafe. It is not currently known when and if an oral medication will again become available in Australia.
Japanese B Encephalitis vaccination is recommended for travellers spending more than 4 weeks in rural areas of Asia, particularly if travel is during the wet season, and if spending a year or more in Asia, even in urban areas. The risk is much greater if spending time near rice paddies and pigs. Western Papua New Guinea is now included in at risk areas, with inadequate knowledge about adjacent areas. In view of the increased risk of significant side effects, vaccines should be advised to remain within "ready access" to medical care for 10 - 14 days post vaccination.
Rabies pre-exposure prophylaxis is strongly recommended for expatriates and travellers who will be spending prolonged periods (i.e. more than a month) in rural parts of rabies endemic areas (Thailand and India and most developing countries, for example), or if working with animals. Whilst emphasising that the injections should be given deep subcutaneously or intramuscularly, the guidelines recognise the WHO practice of supplying vaccination intradermally where the cost of the vaccine is prohibitive. In this situation, the vaccine should be given under the following conditions:
- by a practitioner familiar with and well-versed in the procedure
- in the absence of immunosuppression
- in the absence of concomitant administration of chloroquine or related medications
- with serum rabies antibodies being performed 2 - 3 weeks after the 3rd dose
Post exposure treatment is discussed in detail and likewise should be treated by a practitioner familiar with the management. In this instance, both the vaccine and immunoglobulin are available from the local state or territory health department at no charge to the traveller.
BCG vaccination is noted to be highly effective in children, particularly those under 5 years of age and for whom it is primarily intended if living in areas of high endemnicity (>100 per 100,000) for more than 3 months. The benefits of BCG in adolescents and adults is less certain with efficacy ranging widely from 0 to 80%. Serial Mantoux testing and the newer QuantiferonTM test are likely to be of greater value in other groups.
A yellow fever vaccination certificate is required from travellers over 1 year of age entering Australia within 6 days of having stayed overnight or longer in an infected country, as listed in the Weekly epidemiological record.
Jonathan is Medical Director, Travel Clinics Australia.
Web: www.travelclinic.com.au Email: jcohen@travelclinic.com.au.
