In Australia, as in other industrialised countries, hepatitis A occurs sporadically with periodic epidemic peaks related to point-source and community-wide outbreaks. Notification and hospitalisation rates fell over the last three years. The epidemiology of hepatitis A differs significantly for the Indigenous population, where it has been endemic, compared with the non-Indigenous population. The greater disease burden in Indigenous children has been particularly pronounced in more remote areas. In 1999, an immunisation program commenced for Indigenous children aged 18 months to 6 years living in north Queensland. This was expanded in 2005 to include all Indigenous children aged 12 to 24 months in the Northern Territory, Queensland, South Australia and Western Australia. Continued monitoring should be a priority in Australia, both to assess the impact of these recent changes, and the need for any further expansion of vaccination coverage.82
In the United States, hepatitis A cases decreased substantially following the recommendation of vaccination of children in communities with high rates of disease in 1996, and for states and counties with high hepatitis A notification rates in 1999. In 2006, this was expanded to include all US infants, as part of a staged implementation of progressively expanded vaccination.83
Australia is unique in having a Q fever vaccine available and used in a national program. The National Q fever Management Program (NQFMP), implemented in 2001–2002, promoted and provided screening and vaccination services for those at highest risk of Q fever (meat and livestock industry workers and their families and those working on farms). Subsequently, Q fever notification and hospitalisation rates have declined to record low levels. Both because the program is continuing and because it is difficult to evaluate the contribution of non-program factors (e.g. variations in drought conditions or livestock slaughtering) to reductions in disease, continued and enhanced surveillance will be required in the coming years.
Rotavirus is responsible for a significant number of hospitalisations in Australia each year (around 3,500 hospitalisations were recorded annually with either a principal or non-principal diagnosis of rotavirus). The primary disease burden is in those under five years of age, with hospitalisation most common in the first two years after birth. Two vaccines became available in Australia in 2006 for the prevention of rotavirus gastroenteritis and were recommended for funding under the National Immunisation Program (NIP) for all infants by the Pharmaceutical Benefits Advisory Committee in 2006. The Northern Territory made one of the rotavirus vaccines available free of charge from 1 October 2006 for infants born after 1 August 2006. Universal immunisation of infants in the first six months of life under the NIP should prevent the majority of severe cases of rotavirus and it is anticipated that hospitalisation rates will be substantially reduced. However, it will be important to encourage timeliness of vaccination in order to ensure a maximal impact upon disease. Ongoing analysis of national hospitalisation data will provide valuable data to help assess the impact of a national vaccination program, with laboratory notification in place in the Northern Territory and Queensland and proposed for other jurisdictions.