Abstract: A syphilis outbreak among Australian Aboriginal and Torres Strait Islander people (respectfully referred to as Aboriginal) has resulted in almost 4000 notifications by 2020, with several congenital syphilis cases and infant deaths. Outbreak control efforts became coordinated under a National enhanced test and treat response in 2017. We evaluated the impact of these efforts and of expansion of testing interventions on syphilis prevalence.We developed an individual-based mathematical model of infectious syphilis transmission among young heterosexual Aboriginal people aged 15-34 years living in and move between regional and remote areas with which we assessed the impact of existing and hypothetical outbreak control responses on syphilis prevalence.The increased testing coverage achieved through the response (from 18% to 39% over 2011-2020) could stabilize the epidemic from 2021. To return to pre-outbreak prevalence (<0.24%) by 2025, testing coverage must reach 60%. The addition of annual community-wide screening, where 30% of youth in communities are tested over 6 weeks, would reduce prevalence to the pre-outbreak level within four years. If testing coverage had been scaled-up to 60% at the start of outbreak in mid-2011, the outbreak would have been mitigated.Our results suggest that to control the syphilis outbreak the response needs to be delivered to enable the maximum coverage of testing to be reached in the shortest time in order to reduce the prevalence to pre-outbreak levels. Reduction could be hastened with community-wide screening at similar time periods across all communities together with increases in annual testing coverage.
Hui, Ben B., Ward, James S., Guy, Rebecca, Law, Matthew G., Gray, Richard T., Regan, David G., 2022, Impact of testing strategies to combat a major syphilis outbreak among Australian Aboriginal and Torres Strait Islander peoples: a mathematical modelling study, Journal Article, viewed 05 December 2023, https://www.nintione.com.au/?p=29436.