Epidemiology of syphilis in Australia: moving toward elimination of infectious syphilis from remote Aboriginal and Torres Strait Islander communities?

Abstract

To describe the epidemiology of infectious syphilis among Aboriginal and Torres Strait Islander (Indigenous) people in Australia. We assessed trends in national infectious syphilis notification rates from 2005 to 2009 using Poisson regression, with a focus on geographic and demographic differences by Indigenous status. We compared Indigenous and non-Indigenous rate ratios over the study period and summarised the annual changes (summary rate ratio). Crude notification rates and summary rate ratios by Indigenous status, jurisdiction, sex, age group and area of residence. From 2005 to 2009, in the Indigenous population, there was a substantial decline in the notification rate for infectious syphilis nationally; as well as in the following subgroups: females, 15-29 year olds, and people living in outer regional and remote areas in the Northern Territory and Queensland. In contrast, there was a significant (P < 0.001) upward trend in the notification rate in the non-Indigenous population nationally; as well as in males, in people aged 20 years and over, and in residents of metropolitan and regional areas, New South Wales, Queensland, South Australia, Victoria and Western Australia. The highest summary rate ratios were seen in remote/very remote areas (86.33; 95% CI, 57.45-129.74), in 15-19 year olds (64.65; 95% CI, 51.12-81.78), in females (24.59; 95% CI, 19.73-30.65), and in Western Australia (23.89; 95% CI, 19.82-28.82). These data demonstrate that Australia has two distinct patterns of infectious syphilis: a substantially declining occurrence in Indigenous remote communities and an increasing incidence in males residing in urban and regional areas. Given the decline in notification rates in Indigenous remote communities, now might be the right time to move toward eliminating infectious syphilis from Indigenous communities.