Professor John Murray
School of Mathematics and Statistics
University of New South Wales
Epidemiology looks at the spread of a disease through a community and how interventions can slow that spread or even eradicate the disease. Our main focus is on the spread of HIV in Australia, Papua New Guinea, and the developing world.
The HIV epidemic in Australia
The first case of diagnosed HIV in Australia occurred in the early 1980's and since then the number of HIV infected individuals has grown substantially. The introduction of combination antiretroviral therapy (ART) in the mid-1990's significantly reduced the mortality and morbidity of HIV/AIDS. Since that time the number of people living with HIV infection in Australia has increased. Approximately 90% of new HIV diagnoses occurs in men who have sex with men (MSM). Analysing the number and ages of those diagnosed with HIV infection has shown that the age MSM living with HIV infection is increasing by approximately one year for every two calendar years (Murray et al., Sexual Health, 2009).
The number of HIV-infected individuals living with dementia or neurocognitive impairment in the future in Australia
Since the HIV epidemic is ageing in Australia there is a concern that there will be insufficient resources to cope with these individuals in the future who need extra care due to dementia or neurocognitive impairment. In collaboration with researchers at St Vincent's Hospital we estimated the number of individuals who would need additional care due to these complications out to the year 2030, and the resulting cost to the community (Cysique et al., Sexual Health 2011).
Reduction of the spread of HIV in developing countries: male circumcision
Circumcised men have a 60% lower risk of acquiring HIV infection through heterosexual transmission. A number of trials in sub-Saharan Africa have determined the efficacy of this intervention. Mathematical modelling has then been used by us and other groups to show that increased male circumcision can significantly reduce HIV incidence and lower HIV prevalence in these countries (Londish & Murray, International J Epidemiology, 2008).
The acceptability of male circumcision in Papua New Guinea
Although male circumcision is a promising intervention against HIV acquisition in sub-Saharan Africa where HIV prevalence is higher than 10% on average, it is unclear what impact it would have in lower prevalence countries. Adult HIV prevalence in Papua New Guinea is approximately 1%, the highest in the Pacific region, but much lower than in Africa. Moreover an effective intervention must also be socially acceptable. Two Australian Aid funded projects investigated the acceptability of male circumcision in PNG and also estimated through mathematical modelling the impact on the HIV epidemic in that country.