Background: 

Gay and bisexual men with undiagnosed HIV contribute disproportionately to HIV transmission in Australia.

Methods: 

In 2014 and 2018, we recruited men at gay venues and events in Sydney. Participants self-completed surveys and provided oral fluid samples for HIV testing. We calculated the prevalence of HIV and undiagnosed infection, and assessed changes in behavior, HIV testing, and the use of pre-exposure prophylaxis. We weighted the samples to adjust for differences in where participants were recruited between rounds. Two-sample tests of proportion were used to compare prevalence estimates and χ² tests to assess differences between the samples.

Results: 

In 2014, 944 men were recruited, and 890 men were recruited in 2018. In 2014, the weighted estimate of HIV prevalence was 6.1% [95% confidence intervals (CI): 4.6 to 7.6], of which 13.8% (95% CI: 5.0 to 22.7) was undiagnosed. In 2018, weighted HIV prevalence was 6.4% (95% CI: 4.8 to 8.0), of which 5.3% (95% CI: 0.5 to 11.1) was undiagnosed. Between 2014 and 2018 among all participants, men reporting at least 10 recent casual partners increased from 22.3% to 27.7% (P = 0.008), condomless anal intercourse with casual partners in the previous 6 months increased from 23.9% to 37.3% (P < 0.001), and sexually transmitted infection diagnoses in the previous year increased from 14.4% to 27.5% (P < 0.001). HIV testing and the use of pre-exposure prophylaxis in the previous 6 months increased from 49.6% to 56.3% (P = 0.004) and 2.0%–21.0% (P < 0.001), respectively.

Conclusions: 

Repeated, bio-behavioral surveillance suggests the prevalence of undiagnosed HIV remains low in Sydney, despite gay and bisexual men reporting more casual sex partners, condomless sex, and sexually transmitted infections.

中文翻译：

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在澳大利亚悉尼的男同性恋和双性恋男性中，未确诊的艾滋病毒的持续，低流行，同时发生的是测试和接触前预防措施的增加使用：2014-2018年生物行为研究的重复结果

背景： 

未被诊断出艾滋病毒的男同性恋和双性恋男子在澳大利亚传播艾滋病毒的比例过高。

方法： 

在2014年和2018年，我们在悉尼的同性恋场所和活动中招募了男性。参加者自行完成调查并提供了用于HIV检测的口腔液体样品。我们计算了艾滋病毒和未确诊感染的患病率，并评估了行为变化，艾滋病毒检测以及使用暴露前预防措施。我们对样本进行加权，以调整各轮之间招募参与者的差异。比例的双样本检验用于比较患病率估计和χ ^2次测试，以评估样品之间的差异。

结果： 

2014年，招募了944名男性，2018年招募了890名男性。2014年，艾滋病毒流行率的加权估计为6.1％[95％置信区间（CI）：4.6至7.6]，其中13.8％（95％CI ：5.0到22.7）。2018年，加权的HIV患病率为6.4％（95％CI：4.8至8.0），其中5.3％（95％CI：0.5至11.1）未被诊断。所有参与者之间的2014年和2018年间，男性报告至少10个最近临时性伴，从22.3％上升到27.7％（P = 0.008），condomless肛交与前6个月的休闲伙伴从23.9％提高到37.3％（P < 0.001），而上一年的性传播感染诊断率从14.4％上升到27.5％（P<0.001）。在过去的6个月中，HIV检测和暴露前预防的使用率分别从49.6％增加到56.3％（P = 0.004）和2.0％–21.0％（P <0.001）。

结论： 

反复进行的生物行为监测表明，尽管同性恋者和双性恋男性报告说更多的随意性伴侣，无避孕套性行为和性传播感染，但未诊断出的艾滋病毒在悉尼的患病率仍然很低。