Hui Ben B, Ward James S, Guy Rebecca, Law Matthew G, Gray Richard T, Regan David G
Kirby Institute, UNSW Sydney, Sydney, NSW, Australia.
School of Population Health, University of Queensland, Herston, Queensland, Australia.
Open Forum Infect Dis. 2022 Mar 9;9(5):ofac119. doi: 10.1093/ofid/ofac119. eCollection 2022 May.
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 moving between regional and remote areas, and 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 4 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 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.
澳大利亚原住民和托雷斯海峡岛民（以下统称为原住民）中爆发的梅毒疫情，截至2020年已报告近4000例，其中包括几例先天性梅毒病例和婴儿死亡。2017年，在全国强化检测与治疗应对措施下，疫情防控工作得以协调开展。我们评估了这些措施以及检测干预措施扩大对梅毒流行率的影响。
我们建立了一个基于个体的数学模型，用于模拟15至34岁居住在区域和偏远地区并在这些地区之间流动的年轻异性恋原住民中梅毒的传染性传播，并评估了现有及假设的疫情防控应对措施对梅毒流行率的影响。
通过应对措施实现的检测覆盖率提高（在2011 - 2020年期间从18%提高到39%）可使疫情从2021年起趋于稳定。要在2025年恢复到疫情爆发前的流行率（<0.24%），检测覆盖率必须达到60%。增加年度全社区筛查，即在6周内对社区中30%的年轻人进行检测，将在4年内使流行率降至疫情爆发前的水平。如果在2011年年中疫情爆发开始时检测覆盖率就扩大到60%，疫情本可得到缓解。
我们的结果表明，要控制梅毒疫情，应对措施需要确保在最短时间内实现最大检测覆盖率，以将流行率降至疫情爆发前的水平。通过在所有社区同时进行类似时间段的全社区筛查以及提高年度检测覆盖率，可加快流行率的降低。
