Annual hepatitis C testing and positive tests among gay and bisexual men in Australia from 2016 to 2022: a serial cross-sectional analysis of sentinel surveillance data.

OBJECTIVE: Guidelines recommend annual hepatitis C virus (HCV) testing for gay and bisexual men (GBM) with HIV and GBM prescribed HIV pre-exposure prophylaxis (PrEP). However, there is a limited understanding of HCV testing among GBM. We aimed to examine trends in HCV testing and positivity from 2016 to 2022. METHODS: Using sentinel surveillance data, we examined the proportion of GBM with at least one test and the proportion with a positive test in each year for HCV antibody testing among GBM with no previous HCV positive test, HCV RNA testing among GBM with a positive antibody test but no previous positive RNA test (naïve RNA testing), and HCV RNA testing among people who had a previous RNA positive test and a subsequent negative test (RNA follow-up testing). Trends were examined using logistic regression from 2016 to 2019 and 2020 to 2022. RESULTS: Among GBM with HIV, from 2016 to 2019 antibody testing was stable averaging 55% tested annually. Declines were observed for both naïve HCV RNA testing (75.4%-41.4%: p<0.001) and follow-up HCV RNA testing (70.1%-44.5%: p<0.001). Test positivity declined for HCV antibody tests (2.0%-1.3%: p=0.001), HCV RNA naïve tests (75.4%-41.4%: p<0.001) and HCV RNA follow-up tests (11.3%-3.3%: p=0.001). There were minimal or no significant trends from 2020 to 2022.Among GBM prescribed PrEP, antibody testing declined from 2016 to 2019 (79.4%-69.4%: p<0.001) and was stable from 2020 to 2022. Naïve and follow-up HCV RNA testing was stable with an average of 55% and 60% tested each year, respectively. From 2016-2019, the proportion positive from HCV RNA naïve tests declined (44.1%-27.5%: p<0.046) with no significant change thereafter. Positive follow-up HCV RNA tests fluctuated with no or one new positive test among this group in most years. CONCLUSION: The proportion of GBM with positive HCV tests has declined, however a substantial proportion are not tested annually. A renewed focus on HCV testing, and treatment where required, is warranted to achieve HCV elimination among GBM in Australia.

Measuring Transitions in Sexual Risk Among Men Who Have Sex With Men: The Novel Use of Latent Class and Latent Transition Analysis in HIV Sentinel Surveillance.

New combination human acquired deficiency (HIV) prevention strategies that include biomedical and primary prevention approaches add complexity to the task of measuring sexual risk. Latent transition models are beneficial for understanding complex phenomena; therefore, we trialed the application of latent class and latent transition models to HIV surveillance data. Our aims were to identify sexual risk states and model individuals' transitions between states. A total of 4,685 HIV-negative men who have sex with men (MSM) completed behavioral questionnaires alongside tests for HIV and sexually transmissible infections at one of 2 Melbourne, Victoria, Australia, general practices (2007-2013). We found 4 distinct classes of sexual risk, which we labeled "monogamous" (n = 1,224), "risk minimizer" (n = 1,443), "risk potential" (n = 1,335), and "risk taker" (n = 683). A positive syphilis, gonorrhea, or chlamydia test was significantly associated with class membership. Among a subset of 516 MSM who had at least 3 clinic visits, there was general stability across risk classes; MSM had on average a 0.70 (i.e., 70%) probability of remaining in the same class between visits 1 and 2 and between visits 2 and 3. Monogamous MSM were one exception; the probability of remaining in the monogamous class was 0.51 between visits 1 and 2. Latent transition analyses identified unobserved risk patterns in surveillance data, characterized high-risk MSM, and quantified transitions over time.

Incidence and risk factors associated with chlamydia in men who have sex with men: a cohort analysis of Victorian Primary Care Network for Sentinel Surveillance data.

BACKGROUND: Chlamydia is the most commonly notified sexually transmitted infection (STI) in Australia. Incidence studies of chlamydia in men who have sex with men (MSM) are rare and offer important public health information. OBJECTIVE: To determine chlamydia incidence in MSM presenting at high caseload clinics and describe predictors of infection. METHODS: The Victorian Primary Care Network for Sentinel Surveillance of bloodborne viruses and STIs (VPCNSS) links testing, demographic and behavioural data from individual testers at participating clinics. Data from MSM with more than one chlamydia test at the VPCNSS site between April 2006 and June 2010 were included. Chlamydia incidence per 100 person-years (PY) was calculated and Cox regression used to examine predictors of incidence. RESULTS: 1206 positive tests for chlamydia were detected among 6333 MSM across 11,409 PY of follow-up. Overall chlamydia incidence was 10.6/100 PY (95% CI 10.0 to 11.2) and was highest among MSM aged 16-29 years (12.9/100 PY, 95% CI 11.7 to 14.1), presenting with STI symptoms (16.0/100 PY, 95% CI 14.2 to 18.0), HIV positive (18.5/100 PY, 95% CI 16.6 to 20.6) and self-identified sex workers (14.3/100 PY, 95% CI 10.0 to 20.6). Significant predictors of chlamydia infection among MSM were younger age (adjusted hazard ratio (aHR)=1.9, 95% CI 1.5 to 2.3), self-identifying as a sex worker (aHR=1.6, 95% CI 1.0 to 2.6), being HIV positive (aHR=2.6, 95% CI 1.8 to 3.8), presenting with STI symptoms (aHR=1.7, 95% CI 1.4 to 2.1) and reporting >10 sex partners in the past 6 months (aHR=2.5 95% CI 1.4 to 4.6). CONCLUSION: These results show that MSM represent a key risk population for chlamydia in Australia and identify a number of high-risk MSM subpopulations for whom clinical and public health interventions are warranted.

Utility of risk-based chlamydia testing in primary care: analysis of retrospective surveillance data among women in Melbourne, Australia.

Background Chlamydia (Chlamydia trachomatis) continues to be a public health challenge in Australia, with some contention as to the best screening approach. In the present study we examined chlamydia testing, positivity and sexual behaviour among women with the aim of informing targeted testing among women aged ≥30 years. METHODS: A longitudinal analysis was conducted on retrospective surveillance data collected among women attending general practice, family planning and sexual health clinics participating in sentinel surveillance in Melbourne, Australia. Women were aged ≥16 years and underwent urogenital testing for C. trachomatis (chlamydia) at participating clinics between 2007 and 2014. Chlamydia incidence was calculated as positive chlamydia tests over person-years (PY) among women and reported by 5-year age groups. A Cox regression model examined correlates of a positive chlamydia test among women aged ≥30 years. RESULTS: In all, 36770 women contributed 46432 PY and 52395 chlamydia tests, of which 2895 were positive. The overall chlamydia incidence rate was 6.2 per 100 PY (95% confidence interval (CI) 6.0-6.5). Chlamydia incidence declined with age, plateauing to <5 per 100 PY among women aged ≥30 years. Among women aged ≥30 years, being born in North-East Asia (adjusted hazard ratio (aHR) 2.9; 95% CI 1.9-4.5) and reporting multiple partners (aHR 2.5; 95% CI 1.8-3.5) in the past 12 months were associated with a positive chlamydia test. CONCLUSIONS: Chlamydia control remains challenging in Australia and optimising testing in primary care is a key priority. The results of the present study suggest that, at least among women aged ≥30 years, chlamydia testing should be risk-based and informed by appropriate sexual history taking.

Medication adherence, condom use and sexually transmitted infections in Australian preexposure prophylaxis users.

OBJECTIVE: HIV preexposure prophylaxis (PrEP) decreases risk of HIV acquisition; however, its efficacy is closely dependent on adherence. There is also concern that the preventive effect of PrEP may be offset by risk compensation, notably an increase in condomless anal sex. DESIGN: Multisite, open-label demonstration study that recruited people at current or recent risk of HIV infection in Melbourne, Australia. METHODS: Participants were recruited from three general practice clinics and one sexual health clinic in Melbourne and consented to take daily tenofovir/emtricitabine (TFV/FTC) for 30 months. Sexual practice data, HIV and sexually transmitted infection (STI) test results were collected at baseline and 3-monthly during follow-up. PrEP adherence was evaluated by self-report at clinical visits, online surveys, refill-based assessments and dried blood spot testing. We present a 12-month interim analysis. RESULTS: A total of 114 people were recruited. We observed a significant decline in condom use which occurred concomitantly with a significant increase in STIs over the first 12 months of PrEP. Incidence (per 100 person-years) of any STI was 43.2 and 119.8 at months 0-3 and 3-12, respectively [incidence rate ratio 2.77 (1.52, 5.56)]. Adherence to PrEP medication was high by all measures, including 6 month TFV/FTC levels in dried blood spot. CONCLUSION: We found a significant reduction in condom use and an increase in STIs over the first 12 months of follow-up. High medication adherence rates occurring with a decline in condom use and a rise in STIs, suggest that prevention, early detection and treatment of STIs is a chief research priority in the current era of HIV PrEP.

Trends in detectable viral load by calendar year in the Australian HIV observational database.

BACKGROUND: Recent papers have suggested that expanded combination antiretroviral treatment (cART) through lower viral load may be a strategy to reduce HIV transmission at a population level. We assessed calendar trends in detectable viral load in patients recruited to the Australian HIV Observational Database who were receiving cART. METHODS: Patients were included in analyses if they had started cART (defined as three or more antiretrovirals) and had at least one viral load assessment after 1 January 1997. We analyzed detectable viral load (>400 copies/ml) in the first and second six months of each calendar year while receiving cART. Repeated measures logistic regression methods were used to account for within and between patient variability. Rates of detectable viral load were predicted allowing for patients lost to follow up. RESULTS: Analyses were based on 2439 patients and 31,339 viral load assessments between 1 January 1997 and 31 March 2009. Observed detectable viral load in patients receiving cART declined to 5.3% in the first half of 2009. Predicted detectable viral load based on multivariate models, allowing for patient loss to follow up, also declined over time, but at higher levels, to 13.8% in 2009. CONCLUSIONS: Predicted detectable viral load in Australian HIV Observational Database patients receiving cART declined over calendar time, albeit at higher levels than observed. However, over this period, HIV diagnoses and estimated HIV incidence increased in Australia.