Assessing the effectiveness of HIV/STI risk communication displays among Melbourne Sexual Health Centre attendees: a cross-sectional, observational and vignette-based study.

INTRODUCTION: Increasing rates of sexually transmitted infections (STIs) over the past decade underscore the need for early testing and treatment. Communicating HIV/STI risk effectively can promote individuals' intention to test, which is critical for the prevention and control of HIV/STIs. We aimed to determine which visual displays of risk would be the most likely to increase testing or use of prevention strategies. METHODS: A vignette-based cross-sectional survey was conducted with 662 clients (a median age of 30 years (IQR: 25-36), 418 male, 203 female, 41 other genders) at a sexual health clinic in Melbourne, Australia, between February and June 2023. Participants viewed five distinct hypothetical formats, presented in a randomised order, designed to display the same level of high risk for HIV/STIs: icon array, colour-coded risk metre, colour-coded risk bar, detailed text report and guideline recommendation. They reported their perceived risk, concern and intent to test for each risk display. Associations between the format of the risk display and the intention to test for HIV/STI were analysed using logistic regression. RESULTS: About 378 (57%) of participants expressed that the risk metre was the easiest to understand. The risk metre (adjusted OR (AOR)=2.44, 95% CI=1.49 to 4.01) and risk bar (AOR=2.08, CI=1.33 to 3.27) showed the greatest likelihood of testing compared with the detailed text format. The icon array was less impactful (AOR=0.73, CI=0.57 to 0.94). The risk metre also elicited the most concern but was the most preferred and understood. High-risk perception and concern levels were strongly associated with their intention to have an HIV/STI test. CONCLUSIONS: Displaying risk differently affects an individual's perceived risk of an HIV/STI and influences their intention to test.

Comparison of the patterns of chlamydia and gonorrhoea at the oropharynx, anorectum and urethra among men who have sex with men.

OBJECTIVE: Chlamydia and gonorrhoea are common sexually transmitted infections that infect the oropharynx, anorectum and urethra in men who have sex with men (MSM). This study aimed to examine the pattern of infection at more than one site (multisite) for chlamydia and gonorrhoea among MSM. METHODS: This was a retrospective study of MSM attending the Melbourne Sexual Health Centre for the first time between 2018 and 2019. We included MSM aged ≥16 years who had tested for Neisseria gonorrhoeae and Chlamydia trachomatis at all three sites (oropharynx, anorectum and urethra). We compared infections that occurred at a single site (termed single-site infection) and those that occurred at more than one site (termed multisite infections). RESULTS: Of the 3938 men who were tested for chlamydia and gonorrhoea, 498/3938 men (12.6%, 95% CI 11.5% to 13.6%) had chlamydia at any site, of whom 400/498 (80.3%, 95% CI 78.9% to 81.2%) had single-site chlamydia infection, and 98/498 (19.7%, 95% CI 16.2% to 23.1%) had multisite infections. A similar proportion of men had gonorrhoea at any site (447/3938, 11.4%, 95% CI 10.3% to 12.2%), but among these 447 men, single-site infection was less common (256/447, 57.3%, 95% CI 52.6% to 61.7%, p<0.001) and multisite infection (191/447, 42.7%, 95% CI 38.2% to 47.3%, p<0.001) was more common than chlamydia. There were also marked differences by anatomical site. Urethral infection commonly occurred as single sites (75/122, 61.5%, 95% CI 52.8% to 70.1%) for chlamydia but uncommonly occurred for gonorrhoea (12/100, 12.0%, 95% CI 5.6% to 18.3%, p<0.001). In contrast, anorectal infection uncommonly occurred as multisite infection for chlamydia (98/394, 24.9%, 95% CI 20.6% to 29.1%) but was common (184/309, 59.5%, 95% CI 54.0% to 64.9%, p<0.001) for gonorrhoea. CONCLUSIONS: The markedly different pattern of site-specific infection for chlamydia and gonorrhoea infections among the same MSM suggests significant differences in the transmissibility between anatomical sites and the duration of each infection at each site.

Web-Based Risk Prediction Tool for an Individual's Risk of HIV and Sexually Transmitted Infections Using Machine Learning Algorithms: Development and External Validation Study.

BACKGROUND: HIV and sexually transmitted infections (STIs) are major global public health concerns. Over 1 million curable STIs occur every day among people aged 15 years to 49 years worldwide. Insufficient testing or screening substantially impedes the elimination of HIV and STI transmission. OBJECTIVE: The aim of our study was to develop an HIV and STI risk prediction tool using machine learning algorithms. METHODS: We used clinic consultations that tested for HIV and STIs at the Melbourne Sexual Health Centre between March 2, 2015, and December 31, 2018, as the development data set (training and testing data set). We also used 2 external validation data sets, including data from 2019 as external "validation data 1" and data from January 2020 and January 2021 as external "validation data 2." We developed 34 machine learning models to assess the risk of acquiring HIV, syphilis, gonorrhea, and chlamydia. We created an online tool to generate an individual's risk of HIV or an STI. RESULTS: The important predictors for HIV and STI risk were gender, age, men who reported having sex with men, number of casual sexual partners, and condom use. Our machine learning-based risk prediction tool, named MySTIRisk, performed at an acceptable or excellent level on testing data sets (area under the curve [AUC] for HIV=0.78; AUC for syphilis=0.84; AUC for gonorrhea=0.78; AUC for chlamydia=0.70) and had stable performance on both external validation data from 2019 (AUC for HIV=0.79; AUC for syphilis=0.85; AUC for gonorrhea=0.81; AUC for chlamydia=0.69) and data from 2020-2021 (AUC for HIV=0.71; AUC for syphilis=0.84; AUC for gonorrhea=0.79; AUC for chlamydia=0.69). CONCLUSIONS: Our web-based risk prediction tool could accurately predict the risk of HIV and STIs for clinic attendees using simple self-reported questions. MySTIRisk could serve as an HIV and STI screening tool on clinic websites or digital health platforms to encourage individuals at risk of HIV or an STI to be tested or start HIV pre-exposure prophylaxis. The public can use this tool to assess their risk and then decide if they would attend a clinic for testing. Clinicians or public health workers can use this tool to identify high-risk individuals for further interventions.

Modelling the potential role of saliva use during masturbation in the transmission of Neisseria gonorrhoeae at multiple anatomical sites.

Background Neisseria gonorrhoeae can be cultured from saliva in men with pharyngeal gonorrhoea and could theoretically be transmitted from the pharynx to the urethra when saliva is used as a lubricant for masturbation. In this work, we proposed that saliva use during masturbation may be a potential transmission route of gonorrhoea. Methods We analysed the transmission of Neisseria gonorrhoeae at the oropharynx, urethra and anorectum with mathematical models among men who have sex with men using data from six different studies. Model 1 included transmission routes (oral sex, anal sex, rimming, kissing, and three sequential sex practices). In Model 2, we added saliva use during solo masturbation and mutual masturbation to model 1. Results Model 2 could replicate single site infection at the oropharynx, urethra and anorectum and multi-site infection across six different datasets. However, the calibration of Model 2 was not significantly different from Model 1 across four datasets. Model 2 generated an incidence of gonorrhoea from masturbation of between 5.2% (95% CI: 3.2-10.1) to 10.6% (95% CI: 5.8-17.3) across six data sets. Model 2 also estimated that about one in four cases of urethral gonorrhoea might arise from solo masturbation and mutual masturbation. Conclusions Our models raise the possibility that saliva use during masturbation may play a role in transmitting gonorrhoea. This is an important area to explore because it contributes to the knowledge base about gonorrhoea transmission.

Modelling the contribution that different sexual practices involving the oropharynx and saliva have on Neisseria gonorrhoeae infections at multiple anatomical sites in men who have sex with men.

BACKGROUND: The spectrum of sexual practices that transmit Neisseria gonorrhoeae in men who have sex with men (MSM) is controversial. No studies have modelled potential Neisseria gonorrhoeae transmission when one sexual practice follows another in the same sexual encounter ('sequential sexual practices'). Our aim was to test what sequential practices were necessary to replicate the high proportion of MSM who have more than one anatomical site infected with gonorrhoea ('multisite infection'). METHODS: To test our aim, we developed eight compartmental models. We first used a baseline model (model 1) that included no sequential sexual practices. We then added three possible sequential transmission routes to model 1: (1) oral sex followed by anal sex (or vice versa) (model 2); (2) using saliva as a lubricant for penile-anal sex (model 3) and (3) oral sex followed by oral-anal sex (rimming) or vice versa (model 4). The next four models (models 5-8) used combinations of the three transmission routes. RESULTS: The baseline model could only replicate infection at the single anatomical site and underestimated multisite infection. When we added the three transmission routes to the baseline model, oral sex, followed by anal sex or vice versa, could replicate the prevalence of multisite infection. The other two transmission routes alone or together could not replicate multisite infection without the inclusion of oral sex followed by anal sex or vice versa. CONCLUSIONS: Our gonorrhoea model suggests sexual practices that involve oral followed by anal sex (or vice versa) may be important for explaining the high proportion of multisite infection.

Current operation state of wastewater treatment plants in urban China.

Wastewater treatment plants (WWTPs) in urban China generally face operational difficulties. To comprehensively analyze the current operation status and determine the factors that caused difficulties in urban domestic WWTPs, we conducted a questionnaire survey, and 18 operating conditions of scale-level WWTPs in seven regions in China were investigated. The research results showed that, of the 467-urban domestic WWTPs surveyed in China, approximately 63.17% of the WWTPs' hydraulic loading rates (HLRs) are greater than 80%, 67.02% of the WWTPs have mixed liquor suspended solids (MLSS) concentrations greater than 4000 mg/L, and 95.93% of the WWTPs' mixed liquor volatile suspended solids to mixed liquor suspended solids (MLVSS/MLSS) ratios are lower than 0.7. The WWTP energy consumption accounts for approximately 1% of the national electricity consumption, and approximately 100,000 tons of various chemicals are consumed every year. A high HLR, a high activated sludge concentration and low sludge activity, design value mismatches with actual values, high energy and material consumption, etc. have become the main operational difficulties of urban domestic WWTPs. In this study, the main barriers that hinder improving the operating efficiency of WWTPs were investigated, the causes of operational dilemmas were analyzed, and pathways were jointly explored to solve them. This study may provide valuable implications for industry practitioners with a comprehensive grasp of the industry's current status and related policy formulation.

Diagnosis experiences from 50 hepatitis B patients in Chongqing, China: a qualitative study.

BACKGROUND: The aim of this study was to provide recommendations for reducing the impact of hepatitis B infection on patients with chronic hepatitis B by describing their experiences during the diagnosis process. METHODS: We conducted face-to-face interviews with 50 hepatitis B patients recruited by convenient sampling from an infectious diseases department of a teaching hospital in Chongqing, China from July to August 2019. Thematic analysis framework included interviewees' social demographic characteristics, diagnosis approach, signs and symptoms before diagnosis, feelings after diagnosis, and doctor's instructions. RESULTS: Most patients first detected hepatitis B through various types of physical examinations when the patients were asymptomatic or had only mild symptoms. Most patients were shocked, scared, or overwhelmed when they were diagnosed with hepatitis B. They were able to remember the doctor's instructions about maintaining a healthy lifestyle, but not impressed by the doctor's advice about regular follow-up liver function tests. The lack of regular follow-up has caused irreversible damage to some patients. CONCLUSIONS: Most patients are passively diagnosed with hepatitis B due to their lack of awareness on active hepatitis B prevention. Patients need professional mental health care to overcome the negative emotions that following the diagnosis. Physicians' instruction should emphasize the importance of regular follow-up liver function tests in addition to a healthy lifestyle.

Modeling sulfide production in full flow concrete sewers based on the HRT variation of sewerage.

The corrosion and odor in concrete sewers are mainly related to the sulfide production, which is, under certain circumstances, directly proportional to the hydraulic retention time (HRT) of the sewer. To reduce the corrosion and control the odor in concrete sewers, it is necessary to model the production of sulfide in the concrete sewers with different HRTs. However, previous researches were mostly carried out in simulated Perspex-made sewers, and the obtained theoretical formulas based on the Monod equation were impractical because of the complexity. An actual concrete pipe with domestic sewage was employed in this study to obtain a simple but practical model, which can be applied to quantitively describe the sulfide production according to the HRT of the sewer and the chemical oxygen demand (COD) of the sewage. The empirical equation obtained was rs = (0.045 × lnHRT + 0.071) × ([COD] - b)0.6, the coefficient is a logarithmic function of the HRT, and the sulfide production rate and COD have a power relationship. Based on the data of COD and HRT obtained in the realistic sewer, the production of sulfide in the sewer can be predicted for better maintaining sewers through sulfide control.

Chlamydia trachomatis transmission between the oropharynx, urethra and anorectum in men who have sex with men: a mathematical model.

BACKGROUND: It has been presumed that Chlamydia trachomatis is transmitted between men only through anal or oral sex, but no mathematical models have tested this presumption. METHODS: To test this presumption, we created 20 compartmental mathematical models of different sexual practices that included both oral and anal sex and calibrated these models to the observed rates of Chlamydia trachomatis infection at three anatomical sites from 4888 men who have sex with men (MSM) in Melbourne Sexual Health Centre during 2018-2019. RESULTS: A model that included only oral and anal sex could replicate the observed rates of single-site infection at the oropharynx, urethra and rectum alone, but could not replicate infection at more than one of these sites (multisite). However, if we included transmission from sexual practices that followed one another in the same sexual episode (e.g. saliva contamination of the penis from oral sex transmitting chlamydia to the rectum by anal sex), we significantly improved the calibration of multisite infection rates substantially. CONCLUSIONS: Our modelling study suggests that transmission routes other than just oral and anal sex are necessary to explain the high rate of Chlamydia trachomatis infection at more than one site.

Effects of gibberellin on the activity of anammox bacteria.

The enhancement of gibberellin (GA) on the activity of anaerobic ammonium oxidation(anammox) bacteria in short-term batch experiments(500 mL serum bottle) was studied in this paper. To make sure the accuracy of the data, each experiment group was conducted some statistical analysis. The results showed that GA played an important role in improving anammox activity when the GA dosage ranged from 0.1 to 1.5 mg L-1, and the total nitrogen removal rate (NRR) was increased by 34% when the GA dosage was 1 mg L-1. The monitoring results of extracellular polymeric substances (EPS) and biomass of anammox bacteria indicated that GA addition improved the secretion of EPS and the biomass increasing, whose amount achieved maximum under the GA dose of 1 mg L-1. Compared to the control test, the maximum improvement ratio of the EPS and biomass was 28.6% and 34%, respectively. In addition, the cloning results also indicated that the anammox bacterial community structure shifted in species level of Candidatus Brocadia genus during the experiment, and the most dominant anammox bacteria were Candidatus Brocadia fulgid.

Correction to: Increase in the prevalence of hypertension among adults exposed to the great Chinese famine during early life.

The 'Conclusion' section in the Abstract was published incorrectly in the original publication of the article [1] and is corrected with this erratum as below: "Fetal exposure to the Chinese famine may be associated with an increased risk of hypertension in adulthood in women."

Analysis of key microbial community during the start-up of anaerobic ammonium oxidation process with paddy soil as inoculated sludge.

A sequencing batch reactor (SBR)-anaerobic ammonium oxidation (anammox) system was started up with the paddy soil as inoculated sludge. The key microbial community structure in the system along with the enrichment time was investigated by using molecular biology methods (e.g., high-throughput 16S rRNA gene sequencing and quantitative PCR). Meanwhile, the influent and effluent water quality was continuously monitored during the whole start-up stage. The results showed that the microbial diversity decreased as the operation time initially and increased afterwards, and the microbial niches in the system were redistributed. The anammox bacterial community structure in the SBR-anammox system shifted during the enrichment, the most dominant anammox bacteria were CandidatusJettenia. The maximum biomass of anammox bacteria achieved 1.68×109copies/g dry sludge during the enrichment period, and the highest removal rate of TN achieved around 75%.

Annual variation in the reproductive hormone and behavior rhythm in a population of the Asian short-toed lark: Can spring temperature influence activation of the HPG axis of wild birds?

Although a number of studies have demonstrated a correlation between ambient temperature and the timing of reproductive behavior in many bird species, the relationships between temperature, activation of the hypothalamus-pituitary-gonad (HPG) axis, laying, and hatching in free-living birds, remain unclear. We investigated the relationships between spring temperature, reproductive hormones, and behavior, in a population of the Asian short-toed lark (Calandrella cheleensis) on the Inner Mongolian Grasslands in 2014, 2015 and 2016. LH and T levels peaked earliest in the year with the highest April temperature (2014) and latest in the year with the lowest April temperature (2016), and rose faster in 2014 than in 2015 or 2016. Laying and hatching occurred earliest in 2014 and latest in 2016. E2 also peaked earlier in 2014 than in the other two years but there was no significant difference in peak E2 levels among the three years. The peak of hatching only coincided with the peak in grasshopper nymph (the main food of nestlings) abundance in 2015 and the nestling fledging rate in 2015 was significantly higher than that in 2014 and 2016. We also conducted a controlled experiment on the effect of temperature on plasma LH, T and E2 levels in wild-caught larks, which shows that mean plasma LH, T and E2 levels in the 16°C group all peaked 4days earlier than in the 13°C group. All these results suggest that activation of HPG endocrine axis in the Asia short-toed lark population is closely related to ambient temperature, and that this subsequently influences the timing of laying and hatching. The HPG axis' endocrine function is a physiological factor that mediates effects of ambient temperature on the timing of breeding. Temperature induced annual variation in the timing of hatching was, however, insufficient to synchronize the nestling period with the annual peak in grasshopper nymph abundance. Unusually warm, or cold, spring temperatures advanced, or delayed, grasshopper nymph development to an extent that exceeded the Asian short-toed lark's capacity to advance or delay the onset of breeding and reproductive success was lower in the two years of the study in which the nestling period was asynchronous with the peak of grasshopper nymph abundance. Long-term research on the relationship between the timing of reproduction and population demographics of the Asian short-toed lark is required to understand the effects of climate change on this species and on temperate birds in general.

Increase in the prevalence of hypertension among adults exposed to the Great Chinese Famine during early life.

OBJECTIVE: This study aimed to assess the association between exposure to the Great Chinese Famine (1959-1961) during early life and hypertension in adulthood. METHODS: From July to September 2009, 1224 eligible adults were recruited in a cross-sectional survey using a multi-stage stratified random sampling method in Chongqing China. A questionnaire was used to collect information of hypertension and sociodemographic factors. Participants were categorized as childhood, fetal, and none exposure to famine based on the date of birth. RESULTS: Of the sample, 12.3% reported having hypertension. The prevalence of hypertension varied by famine status: 11.9% in childhood exposure, 16.1% in fetal exposure, and 10.2% in non-exposure group. After adjusting for sociodemographic and lifestyle factors, compared with non-exposure group, fetal exposure group had an increased likelihood of having hypertension with odds ratio of 1.79 (95%CI 1.13-2.84). Although there was no significant gender and famine interaction, the positive association between famine exposure and hypertension was stronger among women than men. CONCLUSION: Fetal exposure to the Chinese famine may be associated with an increased risk of hypertension in adulthood in women [corrected].

Identifying Individuals at High Risk for HIV and Sexually Transmitted Infections With an Artificial Intelligence-Based Risk Assessment Tool.

Background: We have previously developed an artificial intelligence-based risk assessment tool to identify the individual risk of HIV and sexually transmitted infections (STIs) in a sexual health clinical setting. Based on this tool, this study aims to determine the optimal risk score thresholds to identify individuals at high risk for HIV/STIs. Methods: Using 2008-2022 data from 216 252 HIV, 227 995 syphilis, 262 599 gonorrhea, and 320 355 chlamydia consultations at a sexual health center, we applied MySTIRisk machine learning models to estimate infection risk scores. Optimal cutoffs for determining high-risk individuals were determined using Youden's index. Results: The HIV risk score cutoff for high risk was 0.56, with 86.0% sensitivity (95% CI, 82.9%-88.7%) and 65.6% specificity (95% CI, 65.4%-65.8%). Thirty-five percent of participants were classified as high risk, which accounted for 86% of HIV cases. The corresponding cutoffs were 0.49 for syphilis (sensitivity, 77.6%; 95% CI, 76.2%-78.9%; specificity, 78.1%; 95% CI, 77.9%-78.3%), 0.52 for gonorrhea (sensitivity, 78.3%; 95% CI, 77.6%-78.9%; specificity, 71.9%; 95% CI, 71.7%-72.0%), and 0.47 for chlamydia (sensitivity, 68.8%; 95% CI, 68.3%-69.4%; specificity, 63.7%; 95% CI, 63.5%-63.8%). High-risk groups identified using these thresholds accounted for 78% of syphilis, 78% of gonorrhea, and 69% of chlamydia cases. The odds of positivity were significantly higher in the high-risk group than otherwise across all infections: 11.4 (95% CI, 9.3-14.8) times for HIV, 12.3 (95% CI, 11.4-13.3) for syphilis, 9.2 (95% CI, 8.8-9.6) for gonorrhea, and 3.9 (95% CI, 3.8-4.0) for chlamydia. Conclusions: Risk scores generated by the AI-based risk assessment tool MySTIRisk, together with Youden's index, are effective in determining high-risk subgroups for HIV/STIs. The thresholds can aid targeted HIV/STI screening and prevention.

Effect of WeChat-based intervention on food safety knowledge, attitudes and practices among university students in Chongqing, China: a quasi-experimental study.

BACKGROUND: Food safety is of global importance and has been of concern in university settings in recent years. However, effective methods to conduct food safety education are limited. This study aims to evaluate the effects of an intervention on food safety knowledge, attitudes and practices (KAP) by social media, WeChat, among university students. METHODS: A quasi-experimental study was conducted in Chongqing, China. Two departments were recruited randomly from a normal university and a medical university. One department from each university was randomly selected as the intervention group and the other as the control group. All freshmen students in each selected department were chosen to participate in this study. One thousand and twenty-three students were included at baseline, and 444 students completed the study. This intervention was conducted through food safety-related popular science articles with an average of three articles per week released by WeChat official accounts called "Yingyangren" for two months to the intervention group. No intervention was conducted in the control group. An independent t-test was used to test statistical differences in the food safety KAP scores between the two groups. A paired t-test was used to test statistical differences in the food safety KAP scores between before and after the intervention. And quantile regression analysis was conducted to explore the difference between the two groups across the quantile levels of KAP change. RESULTS: After the intervention, compared with control group, participants in the intervention group did not score significant higher on knowledge (p = 0.98), attitude (p = 0.13), and practice (p = 0.21). And the scores of food safety knowledge and practices slightly improved after the intervention both in the intervention group (p = 0.01 and p = 0.01, respectively) and in the control group (p = 0.0003 and p = 0.0001, respectively). Additionally, the quantile regression analysis showed that the intervention had no effect on improving the food safety KAP scores. CONCLUSIONS: The intervention using the WeChat official account had limited effects on improving the food safety KAP among the university students. This study was an exploration of food safety intervention using the WeChat official account; valuable experience can be provided for social media intervention in future study. TRIAL REGISTRATION: ChiCTR-OCH-14004861.

Using machine learning approaches to predict timely clinic attendance and the uptake of HIV/STI testing post clinic reminder messages.

Timely and regular testing for HIV and sexually transmitted infections (STI) is important for controlling HIV and STI (HIV/STI) among men who have sex with men (MSM). We established multiple machine learning models (e.g., logistic regression, lasso regression, ridge regression, elastic net regression, support vector machine, k-nearest neighbour, naïve bayes, random forest, gradient boosting machine, XGBoost, and multi-layer perceptron) to predict timely (i.e., within 30 days) clinic attendance and HIV/STI testing uptake after receiving a reminder message via short message service (SMS) or email). Our study used 3044 clinic consultations among MSM within 12 months after receiving an email or SMS reminder at the Melbourne Sexual Health Centre between April 11, 2019, and April 30, 2020. About 29.5% [899/3044] were timely clinic attendance post reminder messages, and 84.6% [761/899] had HIV/STI testing. The XGBoost model performed best in predicting timely clinic attendance [mean [SD] AUC 62.8% (3.2%); F1 score 70.8% (1.2%)]. The elastic net regression model performed best in predicting HIV/STI testing within 30 days [AUC 82.7% (6.3%); F1 score 85.3% (1.8%)]. The machine learning approach is helpful in predicting timely clinic attendance and HIV/STI re-testing. Our predictive models could be incorporated into clinic websites to inform sexual health care or follow-up service.

A Machine-Learning-Based Risk-Prediction Tool for HIV and Sexually Transmitted Infections Acquisition over the Next 12 Months.

BACKGROUND: More than one million people acquire sexually transmitted infections (STIs) every day globally. It is possible that predicting an individual's future risk of HIV/STIs could contribute to behaviour change or improve testing. We developed a series of machine learning models and a subsequent risk-prediction tool for predicting the risk of HIV/STIs over the next 12 months. METHODS: Our data included individuals who were re-tested at the clinic for HIV (65,043 consultations), syphilis (56,889 consultations), gonorrhoea (60,598 consultations), and chlamydia (63,529 consultations) after initial consultations at the largest public sexual health centre in Melbourne from 2 March 2015 to 31 December 2019. We used the receiver operating characteristic (AUC) curve to evaluate the model's performance. The HIV/STI risk-prediction tool was delivered via a web application. RESULTS: Our risk-prediction tool had an acceptable performance on the testing datasets for predicting HIV (AUC = 0.72), syphilis (AUC = 0.75), gonorrhoea (AUC = 0.73), and chlamydia (AUC = 0.67) acquisition. CONCLUSIONS: Using machine learning techniques, our risk-prediction tool has acceptable reliability in predicting HIV/STI acquisition over the next 12 months. This tool may be used on clinic websites or digital health platforms to form part of an intervention tool to increase testing or reduce future HIV/STI risk.

Critical timing and extent of public health interventions to control outbreaks dominated by SARS-CoV-2 variants in Australia: a mathematical modelling study.

OBJECTIVES: The exact characteristics of a coronavirus disease 2019 (COVID-19) outbreak that trigger public health interventions are poorly defined. The aim of this study was to assess the critical timing and extent of public health interventions to contain COVID-19 outbreaks in Australia. METHODS: A practical model was developed using existing epidemic data in Australia. The effective combinations of public health interventions and the critical number of daily cases for intervention commencement under various scenarios of changes in transmissibility of new variants and vaccination coverage were quantified. RESULTS: In the past COVID-19 outbreaks in four Australian states, the number of reported cases on the day that interventions commenced strongly predicted the size and duration of the outbreaks. In the early phase of an outbreak, containing a wildtype-dominant epidemic to a low level (≤10 cases/day) would require effective combinations of social distancing and face mask use interventions to be commenced before the number of daily reported cases reaches six. Containing an Alpha-dominant epidemic would require more stringent interventions that commence earlier. For the Delta variant, public health interventions alone would not contain the epidemic unless the vaccination coverage was ≥70%. CONCLUSIONS: This study highlights the importance of early and decisive action in the initial phase of an outbreak. Vaccination is essential for containing variants.