Jason J. Ong

Jason J. Ong
London School of Hygiene and Tropical Medicine | LSHTM · Faculty of Infectious and Tropical Diseases, International Diagnostics Centre

PhD, MMed (Hons), FAChSHM, FRACGP, GradDipDIV, MBBS

About

368
Publications
30,166
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2,608
Citations
Citations since 2016
352 Research Items
2574 Citations
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20162017201820192020202120220200400600800
20162017201820192020202120220200400600800
20162017201820192020202120220200400600800
Additional affiliations
July 2012 - November 2015
University of Melbourne
Position
  • PhD

Publications

Publications (368)
Article
Background: Few studies investigate group sex among heterosexuals. The aim of this study was to provide an exploration of characteristics and practices among heterosexual men and women who engage in group sex. Method: We conducted a cross-sectional survey between May 2019 and March 2020 among heterosexual men and women attending a sexual health...
Preprint
BACKGROUND Mobile health (mhealth) interventions among Adolescents and Young Adults (AYA) are increasingly available in African Low- and Middle-Income Countries (LMIC). Its use in overcoming the challenge of verification of HIV self-testing (HIVST) results has improved the scale-up of HIVST services among AYAs. However, there is a challenge in reac...
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Background People on the move, including international migrants, may face health inequities that expose them to a higher risk for HIV than native-born populations. We conducted a systematic review to calculate the HIV prevalence ratio of international migrants compared with native-born populations. Methods We searched five databases between Januar...
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Background We compared the reactive plasma regain (RPR) titre on the day of initial presentation to the day of syphilis treatment to inform clinical practice as to whether a repeat RPR test should be recommended. Methods We undertook a retrospective study between 1-March-2011 and 31-December-2020 at the Melbourne Sexual Health Centre in Australia...
Article
Background: HIV self-testing (HIVST) is effective in improving the uptake of HIV testing among key populations. Complementary data on the economic evaluation of HIVST is critical for planning and scaling up HIVST. This study aimed to evaluate the cost of a community-based organisation (CBO)-led HIVST model implemented in China. Methods: An econo...
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Background Timely diagnosis and treatment of sexually transmitted infections (STIs) underpin their control by reducing the duration of infectiousness. There are currently limited data exploring healthcare seeking among individuals with STI symptoms.Methods We analyzed data on individuals reporting STI symptoms at the Melbourne Sexual Health Centre...
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Background Current rapid tests for syphilis and yaws can detect treponemal and non-treponemal antibodies. We aimed to critically appraise the literature for rapid diagnostic tests (RDTs) which can better distinguish an active infection of syphilis or yaws. Methods We conducted a systematic review and meta-analysis, searching five databases between...
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Background: Timely diagnosis and treatment are crucial for reducing HIV transmission;therefore, estimating the time from HIV infection to antiretroviral therapy (ART) initiation becomes particularly important for people living with HIV. Methods: We used a well-characterised CD4 depletion model to estimate the time from HIV infection to initiatio...
Preprint
Objectives: Gay, bisexual and other men who have sex with men (GBMSM) and trans and gender diverse (TGD) people are disproportionately affected by poorer sexual health outcomes compared to heterosexual populations. We aimed to explore the preferences of GBMSM and TGD for using eHealth for sexual health (eSexualHealth). Methods: We distributed an an...
Article
Background: Age-based sexual mixing data can guide design and implementation of STI control interventions. It can also inform the parameterization of mathematical models of HIV and STI transmission. Data on mixing in heterosexual adults are uncommon, particularly in East Asian regions. Methods: In June 2020, egocentric network data collected fro...
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Background We aimed to systematically review the health preference literature using discrete choice experiments (DCEs), an attribute-based stated preference method, to investigate patient preferences for HIV pre-exposure prophylaxis (PrEP). Methods A search in PubMed, Scopus, CINAHL, and Embase was conducted on July 1, 2021, and updated on Novembe...
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Objectives We assessed nonconventional interventions that did not traditionally focus on increasing condom use and/or testing among men who have sex with men (MSM) and the evidence for these interventions. Methods Guided by the Participants, Concept and Context (PCC) framework, we searched five online databases from inception to 9 August 2021 for...
Article
Background: The sexual and reproductive health care of people with HIV and those at risk of HIV has largely been delivered face-to-face in Australia. These services adapted to the coronavirus disease 2019 (COVID-19) pandemic with a commitment to continued care despite major impacts on existing models and processes. Limited attention has been paid...
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This Special Issue aims to collate the latest evidence-base focused on optimising sexual health services in the 2020s. We discuss why we need specialist sexual health services, how to get the right people to attend, how to strengthen current services, and smarter use of technologies to enhance sexual health services.
Preprint
Objectives Mycoplasma genitalium (MG) disproportionately affects men who have sex with men (MSM). We determined the cost-effectiveness of testing strategies for MG using a healthcare provider perspective. Methods We used inputs from a dynamic transmission model of MG among MSM living in Australia in a decision tree model to evaluate the impact of f...
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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 an...
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Background: With a rise in sexually transmitted infections in Australia, it is important to evaluate and optimise current sexual health services to reduce barriers to access and increase testing. We aimed to describe the range of sexual health services in Australia, focusing on strategies to improve testing among priority populations, and any futu...
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Objectives Population-representative studies of the sexual health of middle-aged and older adults are lacking in ageing societies. This study aimed to identify latent patterns of sexual behaviours and health of people aged 45–74 years. Methods We conducted a latent class analysis of the National Attitudes and Sexual Lifestyles Survey (Natsal-3), a...
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Background: Trichomonas vaginalis is not a notifiable disease in Australia in most states, resulting in limited Australian epidemiological studies. This study aimed to examine the positivity of T. vaginalis in women attending the Melbourne Sexual Health Centre (MSHC) and identify associated factors. Methods: All women aged ≥16 years who were tes...
Preprint
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Introduction Globally, there are approximately 58 million people with chronic hepatitis C virus infection (HCV) but only 20% have been diagnosed. HCV self-testing (HCVST) could reach those who have never been tested and increase access and uptake of HCV testing services. We compared cost per HCV diagnosis or cure for HCVST versus facility-based HCV...
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Purpose of Review This scoping review summarises the literature on HIV prevention and management interventions utilizing behavioural economic principles encapsulated in the MINDSPACE framework. Recent Findings MINDSPACE is an acronym developed by the UK’s behavioural insights team to summarise nine key influences on human behaviour: Messenger, Inc...
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Background Men who have sex with men (MSM) practicing exclusively receptive anal sex are more likely to present with secondary than primary syphilis, implying primary anorectal lesions may be missed. If men could detect anorectal lesions by regular anal self-examination, the duration of infectiousness could be reduced. This study aimed to examine a...
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IntroductionOverseas-born and newly arrived gay and bisexual men and men who have sex with men (GBMSM) are at higher risk of acquiring HIV in comparison to Australian-born GBMSM. Pre-exposure prophylaxis (PrEP) is subsidized by the Australian government under Medicare, Australia's universal health insurance scheme, however many members of this popu...
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Background Understanding the natural history of anal high-risk human papillomavirus (hrHPV) infection is key for designing anal cancer prevention programmes but has not been systematically characterised. Methods We reanalysed data from 34 studies with 16 164 individuals in six risk groups defined by HIV status, gender, and male sexuality: men who...
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Objectives: To compare the usability and acceptability of oral fluid- and blood-based HIV self-test kits among men who have sex with men in Australia. Design: Randomised crossover trial. Setting, participants: Gay, bisexual, and other men aged 18 years or older who have sex with men, who attended two metropolitan sexual health clinics in Sydne...
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Rises in condomless anal sex among men who have sex with men (MSM) have been reported over the last decade but there is less certainty about the role that drugs, alcohol, play in this change. We examined the changes in drug and alcohol use among 22,255 MSM reporting condomless anal sex at Melbourne Sexual Health Centre in 2011–2017. There was a 7%...
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There is a rich literature on sexualized drug use (i.e., drug use before or during sex) for men who have sex with men but less data from female sex workers (FSW), particularly from low- and middle-income countries. We describe the sexual and reproductive health outcomes in FSW reporting sexualized drug use. In 2019, we conducted a cross-sectional s...
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Behavioral economics and its applied branch “nudging” can improve individual choices in various health care settings. However, there is a paucity of research using nudges to improve regular testing for HIV and other sexually transmitted infections (STIs). The study examined which reminder system and message type men who have sex with men (MSM) pref...
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Despite rises in sexually transmitted infection (STI) notifications among Australian women in the last decade, limited STI surveillance data exist specifically for women who have sex with women. This study aimed to compare differences in sexual practices and positivity for STIs and other genital infections among women who have sex with men only (WS...
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Background China has low seasonal influenza vaccination rates among priority populations. In this study, we aimed to evaluate a pay-it-forward strategy to increase influenza vaccine uptake in rural, suburban, and urban settings in China. Methods We performed a quasi-experimental pragmatic trial to examine the effectiveness of a pay-it-forward inte...
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Objectives To illustrate the epidemiologic and cost-effectiveness impact of shifting the focus from population-based screening toward a targeted management approach for genital chlamydia infection. Design Modeling study, implementing an individual-based, stochastic, dynamic network model. Setting Hong Kong. Population A hypothetical sample netwo...
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Bacterial sexually transmitted infections (STIs) are rising relentlessly in virtually every country and among most risk groups. These infections have substantial individual and community consequences and costs. This review summarises the evidence for the effectiveness of different strategies to control STIs and assumes countries have sufficient fin...
Preprint
Introduction: Of 37.7 million people living with HIV in 2020, 6.1 million still do not know their HIV status. We synthesise evidence on concurrent HIV testing among people who tested for other sexually transmitted infections (STI). Methods: We conducted a systematic review using five databases, HIV conferences and clinical trial registries. We incl...
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Background Despite being vaccine-preventable, hepatitis A virus (HAV) outbreaks occur among men who have sex with men (MSM). We modelled the cost-effectiveness of vaccination strategies to prevent future outbreaks. Methods A HAV transmission model was calibrated to HAV outbreak data for MSM in England over 2016-2018, producing estimates for the ba...
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We aimed to investigate the sexual mixing by human papillomavirus (HPV) vaccination status in male-male partnerships and estimate the proportion of male-male partnerships protected against HPV. We analyzed male-male partnerships attending the Melbourne Sexual Health Center between 2018 and 2019. Data on self-reported HPV vaccination status were col...
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Studies suggest men who have sex with men (MSM) practising receptive anal sex are more likely to present with secondary syphilis, implying primary anorectal lesions are likely to be missed. If men could detect anorectal lesions in the primary stage by regular anal self-examination (ASE), transmission could be reduced by early diagnosis and treatmen...
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Background: Social network approaches to testing allow individuals (indexes) to distribute tests to social networks (alters). This quasi-experimental study compared two social network-based testing strategies in promoting human immunodeficiency virus (HIV) testing among Chinese gay, bisexual, and other men who have sex with men (GBMSM). Methods:...
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Background Australia implemented an mRNA-based booster vaccination strategy against the COVID-19 Omicron variant in November 2021. We aimed to evaluate the effectiveness and cost-effectiveness of the booster strategy over 180 days. Methods We developed a decision-analytic Markov model of COVID-19 to evaluate the cost-effectiveness of a booster str...
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Objectives: Despite a high risk of human papillomavirus (HPV) infection among men who have sex with men (MSM), few have ever tested. This study aimed to evaluate the feasibility and accuracy of HPV self-sampling among Chinese MSM, with the purpose of measuring the feasibility of self-sampling as an alternative in HPV testing scenarios. Methods:...
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Background Hepatitis C virus self-testing (HCVST) may increase test uptake especially among marginalized key populations such as men who have sex with men (MSM). We conducted an observational study to assess the usability, acceptability and feasibility of HCVST among MSM in China. Methods An observational study with convenience sampling was perfor...
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Objectives: Azithromycin is commonly used to treat Neisseria gonorrhoeae. We compared its gastrointestinal side effects using 1 g single, 2 g single or 2 g split (i.e. 1 g plus 1 g 6-12 h later) dosing, representing our clinic's changing guidelines over the study period. Methods: We recruited consecutive sexual health clinic patients who received a...
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Objectives Azithromycin is commonly used to treat Neisseria gonorrhoeae. We compared its gastrointestinal side effects using 1 g single, 2 g single or 2 g split (i.e. 1 g plus 1 g 6–12 h later) dosing, representing our clinic’s changing guidelines over the study period. Methods We recruited consecutive sexual health clinic patients who received az...
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Background Poor adherence to oral HIV pre-exposure prophylaxis (PrEP) diminishes its clinical and public health benefits. This study synthesises evidence regarding discontinuation, adherence, and reinitiation of PrEP among geographically diverse PrEP users. Methods We did a systematic review and meta-analysis evaluating studies published in MEDLIN...
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Introduction: Due to the effectiveness of combined antiretroviral therapy and its growing availability worldwide, most people living with HIV (PLHIV) have a near-normal life expectancy. However, PLHIV continue to face various health and social challenges that severely impact their health-related quality-of-life (HRQoL). The UNAIDS Global AIDS Stra...
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Background In Australia, undiagnosed HIV rates are much higher among migrant gay, bisexual, or other men who have sex with men (GBMSM) than Australian-born GBMSM. HIV self-testing is a promising tool to overcome barriers to HIV testing and improve HIV testing uptake among migrant GBMSM. We compared the preferences for HIV testing services, includin...
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Improving access to sexual health services is critical in light of rising sexually transmitted infections (STIs). We evaluated a hub-and-spoke model for improving access to sexual health services in three general practices in Victoria, Australia. The primary outcome was the impact on HIV and STI (chlamydia, gonorrhoea, syphilis) testing. Segmented...
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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...
Preprint
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Purpose of review Improving HIV testing uptake is essential to ending the HIV pandemic. HIV testing approaches can be opt-in, opt-out or risk-based. This systematic review examines and compares the uptake of HIV testing in opt-in, opt-out and risk-based testing approaches. Recent findings There remains missed opportunities for HIV testing in a var...
Article
In November 2021, clients attending the Melbourne Sexual Health Centre were invited to participate in the Annual Client Satisfaction Survey by receiving an SMS link at 5:15pm on the day they attended the clinic. We analysed the response time data and found that most (60%; 168/278) individuals responded to the survey during the time period 5:00-5:59...
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Background: Individuals who have both opposite- and same-sex partners have the potential to pass sexually transmitted infections (STIs) between high- and low-risk populations. Our aim was to examine assortative sexual mixing in terms of same-sex activity among male-female partnerships. Methods: This was a retrospective repeated cross-sectional s...
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Background: Regular testing for HIV and other sexually transmitted infections (STI) is recommended at least annually for sexually active men who have sex with men (MSM) in most high-income countries. To encourage regular use of HIV and STI testing and treatment services for MSM, we reviewed the literature to summarise the attributes of an HIV/STI t...
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Background Asian-born gay, bisexual and other men who have sex with men (gbMSM) newly arrived in Australia are more than four times as likely than their Australian-born counterparts to be diagnosed with incident HIV. Our aim was to explore experiences of Asian-born gbMSM newly arrived in Australia and attending a sexual health centre with regards t...
Preprint
BACKGROUND HIV self-testing (HIVST) has been rapidly scaled up and additional strategies further expand testing uptake. Secondary distribution has people (indexes) apply for multiple kits and pass these kits to people (alters) in their social networks. However, identifying key influencers is difficult. OBJECTIVE This study aimed to develop an inno...
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Background: Low syphilis testing uptake is a major public health issue among men who have sex with men (MSM) in many low- and middle-income countries. Syphilis self-testing (SST) may complement and extend facility-based testing. We aimed to evaluate the effectiveness and costs of providing SST on increasing syphilis testing uptake among MSM in Chi...
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Objectives Molecular testing for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) is costly. We appraised the evidence regarding pooling samples from multiple individuals to test for CT/NG. Methods In this systematic review, we searched five databases (2000-2021). Studies were included if they contained primary data describing pooled test...
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Background Lymphogranuloma venereum (LGV) is caused by Chlamydia trachomatis serovars L1-L3. This study determined the positivity for LGV testing before and after introduction of universal LGV testing of positive rectal Chlamydia trachomatis samples in men who have sex with men (MSM). Methods From March 2015 to February 2018, MSM with rectal C. tr...
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Background: Regular anal self-examination could potentially reduce syphilis transmission by detecting anal syphilis earlier among men who have sex with men (MSM). This study aimed to examine the preferences of MSM on performing anal self-examination to detect anal syphilis. Methods: An online survey with a discrete choice experiment (DCE) was di...
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Background Estimating the population sizes of key populations(people who inject drugs, men who have sex with men, transgender persons, and commercial sex workers) is critical for understanding the overall Human Immunodeficiency Virus burden. This scoping review aims to synthesize existing methods for population size estimation among key populations...
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Background There is a significant global burden of herpes simplex virus (HSV) related genital ulcer disease yet little is known about its impact on quality of life. This systematic review aimed to identify studies that quantitatively evaluated the effect of genital herpes on various aspects of health-related quality of life. Methods Six databases...
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Background Digital network–based methods may enhance peer distribution of HIV self-testing (HIVST) kits, but interventions that can optimize this approach are needed. We aimed to assess whether monetary incentives and peer referral could improve a secondary distribution program for HIVST among men who have sex with men (MSM) in China. Methods and...
Preprint
Improving access to sexual health services is critical in light of rising sexually transmitted infections (STIs). We evaluated a Hub and Spoke model for improving access to sexual health services in three general practices in Victoria, Australia. The primary outcome was the impact on HIV and STI (chlamydia, gonorrhoea, syphilis) testing. Segmented...
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Full-text available
Purpose of review Effective ways to diagnose the remaining people living with HIV who do not know their status are a global priority. We reviewed the use of risk-based tools, a set of criteria to identify individuals who would not otherwise be tested (screen in) or excluded people from testing (screen out). Recent findings Recent studies suggest t...
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Background China has the highest prevalence of hepatitis B virus (HBV) infection worldwide. Universal HBV screening might enable China to reach the WHO 2030 target of 90% diagnostics, 80% treatment, and 65% HBV-related death reduction, and eventually elimination of viral hepatitis. We evaluated the cost-effectiveness of implementing universal HBV s...
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Although HIV self-testing (HIVST) has expanded in many regions, a few HIVST services have been tailored for and organized by youth. Innovative HIVST models are needed to differentiate testing services and generate local demand for HIVST among youth. The current pilot study aimed at examining the feasibility and efficacy of crowdsourced youth-led st...
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Human immunodeficiency virus self-testing (HIVST) is an innovative and effective strategy important to the expansion of HIV testing coverage. Several innovative implementations of HIVST have been developed and piloted among some HIV high-risk populations like men who have sex with men (MSM) to meet the global testing target. One innovative strategy...
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Objectives: Genital Ulcer Disease (GUD) carries a significant disease burden globally. With limited access to diagnostics, the 2001 World Health Organization (WHO) sexually transmitted illnesses (STI) guidelines proposed a syndromic management algorithm that required a clinical decision to determine the management of GUD. We assessed the diagnostic...