Treatment for prevention of HIV transmission in a localised epidemic: the case for South Australia

Sexual Health ◽  
2011 ◽  
Vol 8 (3) ◽  
pp. 280 ◽  
Author(s):  
Kelly-Jean Heymer ◽  
David P. Wilson
Keyword(s):  
Hiv Transmission ◽  
South Australia ◽  
Hiv Infections ◽  
Small Population ◽  
Transmission Model ◽  
Minimal Impact ◽  
Gay Community ◽  
Epidemiological Impact ◽  
Sex With Men ◽  
Novel Model

Background Discussion is currently taking place among international HIV/AIDS groups around increasing HIV testing and initiating earlier use of antiretroviral therapy (ART) among people diagnosed with HIV as a method to reduce the spread of HIV. In this study, we explore the expected epidemiological impact of this strategy in a small population in which HIV transmission is predominantly confined to men who have sex with men (MSM). Methods: A deterministic mathematical transmission model was constructed to investigate the impacts of strategies that increase testing and treatment rates, and their likely potential to mitigate HIV epidemics among MSM. Our novel model distinguishes men in the population who are more easily accessible to prevention campaigns through engagement with the gay community from men who are not. This model is applied to the population of MSM in South Australia. Results: Our model-based findings suggest that increasing testing rates alone will have minimal impact on reducing the expected number of infections compared to current conditions. However, in combination with increases in treatment coverage, this strategy could lead to a 59–68% reduction in the number of HIV infections over the next 5 years. Targeting men who are socially engaged with the gay community would result in the majority of potential reductions in incidence, with only minor improvements possible by reaching all other MSM. Conclusions: Investing in strategies that will achieve higher coverage and earlier initiation of treatment to reduce infectiousness of HIV-infected individuals could be an effective strategy for reducing incidence in a population of MSM.

Importance of promoting HIV testing for preventing secondary transmissions: modelling the Australian HIV epidemic among men who have sex with men

Sexual Health ◽  
2009 ◽  
Vol 6 (1) ◽  
pp. 19 ◽  
Author(s):  
David P. Wilson ◽  
Alexander Hoare ◽  
David G. Regan ◽  
Matthew G. Law
Keyword(s):  
Hiv Testing ◽  
Early Treatment ◽  
Hiv Transmission ◽  
Public Health Intervention ◽  
Population Level ◽  
Hiv Infections ◽  
Long Term Effects ◽  
Wide Range ◽  
Epidemiological Impact ◽  
Sex With Men

Background: We address the research questions: (i) what proportion of new HIV infections is transmitted from people who are (a) undiagnosed, (b) in primary HIV infection (PHI), (c) on antiretroviral therapy?; and (ii) what is the expected epidemiological impact of (a) increasing the proportion of newly acquired HIV infections receiving early treatment, and (b) increasing HIV testing rates? Methods: We used a mathematical model to simulate HIV transmission in the population of men who have sex with men (MSM) in Australia. We calibrated the model using established biological and clinical data and a wide range of Australian MSM epidemiological and behavioural data sources. Results: We estimate that ~19% of all new HIV infections are transmitted from the ~3% of Australian HIV-infected MSM who are in PHI; ~31% of new HIV infections are estimated to be transmitted from the ~9% of MSM with undiagnosed HIV. We estimate that the average number of infections caused per HIV-infected MSM through the duration of PHI is ~0.14–0.28. Conclusions: The epidemiological impact of increasing treatment in PHI would be modest due to insufficient detection of newly-infected individuals. In contrast, increases in HIV testing rates could have substantial epidemiological consequences. The benefit of testing will also increase over time. Promoting increases in the coverage and frequency of testing for HIV could be a highly-effective public health intervention, but the population-level impact of interventions based on promoting early treatment of patients diagnosed in PHI is likely to be small. Treating PHI requires further evaluation of its long-term effects on HIV-infected individuals.

Impact of frequent testing on the transmission of HIV and N. gonorrhoeae among men who have sex with men: a mathematical modelling study

2019 ◽  
Vol 96 (5) ◽  
pp. 361-367
Author(s):  
Maarten Reitsema ◽  
Janneke Heijne ◽  
Maartje Visser ◽  
Ard van Sighem ◽  
Maarten Schim van der Loeff ◽  
...  
Keyword(s):  
Hiv Infection ◽  
Hiv Transmission ◽  
Hiv Infections ◽  
Anal Intercourse ◽  
Transmission Model ◽  
Prevention Measures ◽  
Condomless Anal Intercourse ◽  
Frequent Testing ◽  
Sex With Men ◽  
The Impact

ObjectivesTo investigate the impact and efficiency of combined testing for HIV and other STIs on HIV and STI transmission among men who have sex with men (MSM) and to assess what subgroups of MSM should be targeted for frequent testing.MethodsWe developed an agent-based transmission model that simulates infection with HIV or Neisseria gonorrhoeae (NG) among MSM. We examined scenarios with increased percentages of MSM getting tested six monthly, among all MSM or only specific subgroups of MSM (defined according to recent gonorrhoea, number of partners and engagement in condomless anal intercourse (CAI)) and scenarios with reduced intervals between HIV/STI tests.ResultsThe most efficient strategies were those with increased percentage of MSM getting tested every 6 months among MSM with a recent gonorrhoea diagnosis; or among MSM who had CAI and ≥10 partners; or MSM who had ≥10 partners. Over 10 years, these strategies resulted in 387–718 averted HIV infections and required 29–164 additional HIV tests per averted HIV infection or one to seven additional gonorrhoea tests per averted NG infection. The most effective strategy in reducing HIV transmission was the one where the intervals between tests were reduced by half, followed by the strategy with increased percentage of MSM getting tested every 6 months among all MSM. Over 10 years, these strategies resulted in 1362 and 1319 averted HIV infections, but required 663 and 584 additional HIV tests per averted HIV infection, respectively.ConclusionsTargeting MSM with recent gonorrhoea diagnosis or MSM with many partners is efficient in terms of HIV/STI tests needed to prevent new HIV or NG infections. Major reductions in HIV incidence can be achieved with consistent HIV/STI testing every 6 months among larger groups, including low-risk MSM. To impede HIV transmission, frequent testing should be combined with other prevention measures.

scholarly journals Evaluation of HIV Transmission Clusters among Natives and Foreigners Living in Italy

Viruses ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 791 ◽  
Author(s):  
Lavinia Fabeni ◽  
Maria Mercedes Santoro ◽  
Patrizia Lorenzini ◽  
Stefano Rusconi ◽  
Nicola Gianotti ◽  
...  
Keyword(s):  
Hiv Transmission ◽  
Phylogenetic Analyses ◽  
Hiv Infections ◽  
Public Health Response ◽  
Health Response ◽  
Drug Naïve ◽  
Recent Diagnosis ◽  
Sex With Men ◽  
Italian Origin ◽  
Hiv 1

We aimed at evaluating the characteristics of HIV-1 molecular transmission clusters (MTCs) among natives and migrants living in Italy, diagnosed between 1998 and 2018. Phylogenetic analyses were performed on HIV-1 polymerase (pol) sequences to characterise subtypes and identify MTCs, divided into small (SMTCs, 2–3 sequences), medium (MMTCs, 4–9 sequences) and large (LMTCs, ≥10 sequences). Among 3499 drug-naïve individuals enrolled in the Italian Cohort Naive Antiretroviral (ICONA) cohort (2804 natives; 695 migrants), 726 (20.8%; 644 natives, 82 migrants) were involved in 228 MTCs (6 LMTCs, 36 MMTCs, 186 SMTCs). Migrants contributed 14.4% to SMTCs, 7.6% to MMTCs and 7.1% to LMTCs, respectively. HIV-1 non-B subtypes were found in 51 MTCs; noteworthy was that non-B infections involved in MTCs were more commonly found in natives (n = 47) than in migrants (n = 4). Factors such as Italian origin, being men who have sex with men (MSM), younger age, more recent diagnosis and a higher CD4 count were significantly associated with MTCs. Our findings show that HIV-1 clustering transmission among newly diagnosed individuals living in Italy is prevalently driven by natives, mainly MSM, with a more recent diagnosis and frequently infected with HIV-1 non-B subtypes. These results can contribute to monitoring of the HIV epidemic and guiding the public health response to prevent new HIV infections.

scholarly journals Antiretroviral therapy for prevention of HIV transmission: implications for Europe

2013 ◽  
Vol 18 (48) ◽  
Author(s):  
V Cambiano ◽  
J O’Connor ◽  
A N Phillips ◽  
A Rodger ◽  
R Lodwick ◽  
...  
Keyword(s):  
Antiretroviral Therapy ◽  
People Who Inject Drugs ◽  
Hiv Transmission ◽  
Controlled Trial ◽  
Population Level ◽  
Hiv Infections ◽  
Cd4 Count ◽  
Art Initiation ◽  
Sex With Men ◽  
Randomised Controlled

The aim of this review is to summarise the evidence on the population-level effect of antiretroviral therapy (ART) in preventing HIV infections, and to discuss potential implications in the European context of recommending starting ART when the CD4 count is above 350 cells/mm3. The ability of ART to reduce the risk of HIV transmission has been reported in observational studies and in a randomised controlled trial (HPTN 052), in which ART initiation reduced HIV transmission by 96% within serodiscordant couples. As yet, there is no direct evidence for such an effect among men having sex with men or people who inject drugs. HPTN 052 led international organisations to develop recommendations with a higher CD4 threshold for ART initiation. However, there remains a lack of strong evidence of clinical benefit for HIV-positive individuals starting ART with CD4 count above 350 cells/mm3. The main goal of ART provision should be to increase ART coverage for all those in need, based on the current guidelines, and the offer of ART to those who wish to reduce infectivity; increased HIV testing is therefore a key requirement. Other proven prevention means such as condom use and harm reduction for people who inject drugs remain critical.

scholarly journals Modeling an Integrated HIV Prevention and Care Continuum to Achieve the Ending the HIV Epidemic Goals

2020 ◽  
Author(s):  
Samuel M. Jenness ◽  
Jordan A. Johnson ◽  
Karen W. Hoover ◽  
Dawn K. Smith ◽  
Kevin P. Delaney
Keyword(s):  
Hiv Prevention ◽  
Hiv Transmission ◽  
Relative Increase ◽  
Retention Rates ◽  
Hiv Care ◽  
Transmission Model ◽  
Hiv Screening ◽  
Substantial Impact ◽  
Hiv Epidemic ◽  
Sex With Men

ABSTRACTObjectiveWe sought to evaluate which combinations of HIV prevention and care activities would have the greatest impact towards reaching the US Ending the HIV Epidemic (EHE) plan goals of reducing HIV incidence at least 75% by 2025 and 90% by 2030.DesignA stochastic HIV transmission model for men who have sex with men (MSM), calibrated to local surveillance estimates in the Atlanta area, a focal EHE target jurisdiction.MethodsModel scenarios varied HIV screening rates relative to current levels, under different assumptions of how HIV-negative MSM would be linked to PrEP initiation, and also considered improvements to HIV care linkage and retention for those screening positive.ResultsA 10-fold relative increase in HIV screening rates (to approximately biannual screening for black and Hispanic MSM and quarterly for white MSM) would lead to 43% of infections averted if integrated with PrEP initiation. Improvements to HIV care retention would avert 41% of infections if retention rates were improved 10-fold. If both screening and retention were jointly improved 10-fold, up to 74% of cumulative infections would be averted. Under this scenario, it would take 4 years to meet the 75% EHE goal and 12 years to meet the 90% goal for MSM in Atlanta.ConclusionsInterventions to improve HIV screening linked with PrEP for those screening negative, and HIV care retention would have a substantial impact on HIV prevention. However, additional interventions may be necessary to reach the EHE goal of a 90% reduction in incidence for Atlanta MSM by 2030.

scholarly journals The Effect of Monitoring Viral Load and Tracing Patients Lost to Follow-up on the Course of the HIV Epidemic in Malawi: A Mathematical Model

2018 ◽  
Vol 5 (5) ◽  
Author(s):  
Janne Estill ◽  
Cliff C Kerr ◽  
Nello Blaser ◽  
Luisa Salazar-Vizcaya ◽  
Lyson Tenthani ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Viral Load ◽  
Hiv Transmission ◽  
Scale Up ◽  
Hiv Infections ◽  
Transmission Model ◽  
Speed Test ◽  
Treatment Interruptions ◽  
Lost To Follow Up

Abstract Background Antiretroviral therapy (ART) reduces HIV transmission, but treated patients may again become infectious. We used a mathematical model to determine whether ART as prevention is more effective if viral load (VL) is routinely monitored and patients lost to follow-up (LTFU) traced. Methods We simulated ART cohorts to parameterize a deterministic transmission model calibrated to Malawi. We investigated the following strategies for improving treatment and retention: monitoring VL every 12 or 24 months, tracing patients LTFU, or a generic strategy leading to uninterrupted treatment. We tested 3 scenarios, where ART scale-up continues at current (Universal ART), reduced (Failed scale-up), or accelerated speed (Test&Treat). Results In the Universal ART scenario, between 2017 and 2020 (2050), monitoring VL every 24 months prevented 0.5% (0.9%), monitoring every 12 months prevented 0.8% (1.4%), tracing prevented 0.3% (0.5%), and uninterrupted treatment prevented 5.5% (9.9%) of HIV infections. Failed scale-up resulted in 25% more infections than the Universal ART scenarios, whereas Test&Treat resulted in 7%–8% less. Conclusions Test&Treat reduces transmission of HIV, despite individual cases of treatment failure and ART interruption. Whereas viral load monitoring and tracing have only a minor impact on transmission, interventions that aim to minimize treatment interruptions can further increase the preventive effect of ART.

scholarly journals HIV incidence among gay men and other men who have sex with men in 2020: where is the epidemic heading?

Sexual Health ◽  
2017 ◽  
Vol 14 (1) ◽  
pp. 5 ◽  
Author(s):  
Shauna Stahlman ◽  
Carrie Lyons ◽  
Patrick S. Sullivan ◽  
Kenneth H. Mayer ◽  
Sean Hosein ◽  
...  
Keyword(s):  
Hiv Transmission ◽  
Hiv Infections ◽  
Retention In Care ◽  
Hiv Treatment ◽  
Treatment As Prevention ◽  
Structural Level ◽  
Hiv Incidence ◽  
Hiv Risks ◽  
Sex With Men ◽  
Hiv Acquisition

The goal to effectively prevent new HIV infections among gay, bisexual, and other men who have sex with men (MSM) is more challenging now than ever before. Despite declines in the late 1990s and early 2000s, HIV incidence among MSM is now increasing in many low- and high-income settings including the US, with young, adolescent, and racial/ethnic minority MSM being among those at highest risk. Potentiating HIV risks across all settings are individual-, network-, and structural-level factors such as stigma and lack of access to pre-exposure prophylaxis (PrEP) and antiretroviral treatment as prevention. To make a sustained impact on the epidemic, a concerted effort must integrate all evidence-based interventions that will most proximally decrease HIV acquisition and transmission risks, together with structural interventions that will support improved coverage and retention in care. Universal HIV treatment, increased access to HIV testing, and daily oral PrEP have emerged as integral to the prevention of HIV transmission, and such efforts should be immediately expanded for MSM and other populations disproportionately affected by HIV. Respect for human rights and efforts to combat stigma and improve access to prevention services are needed to change the trajectory of the HIV pandemic among MSM.

HIV incidence trends vary between jurisdictions in Australia: an extended back-projection analysis of men who have sex with men

Sexual Health ◽  
2012 ◽  
Vol 9 (2) ◽  
pp. 138 ◽  
Author(s):  
Kylie-Ann Mallitt ◽  
David P. Wilson ◽  
Ann McDonald ◽  
Handan Wand
Keyword(s):  
South Australia ◽  
Hiv Infections ◽  
Surveillance Data ◽  
Hiv Incidence ◽  
Back Projection ◽  
Hiv Diagnosis ◽  
Incidence Trends ◽  
The Past ◽  
Sex With Men ◽  
Incident Cases

Background Trends in HIV diagnoses differ across Australia and are primarily driven by men who have sex with men (MSM). We use national population surveillance data to estimate the incidence of HIV infections among MSM by jurisdiction and infer the proportion of undiagnosed infections. Methods: Annual surveillance data for AIDS diagnoses, HIV diagnoses and recently acquired HIV infections were obtained from 1980 to 2009. A modified statistical back-projection method was used to reconstruct HIV incidence by jurisdiction. Results: HIV incidence among MSM peaked for all jurisdictions in the early 1980s and then declined into the early 1990s, after which incidence increased. Trends then differ between jurisdictions. In New South Wales (NSW) and South Australia, estimated HIV incidence peaked at 371 and 50 cases respectively in 2003, and has since decreased to 258 and 24 cases respectively in 2009. HIV infections in Queensland (Qld) have more than doubled over the past decade, from 84 cases in 2000 to 192 cases in 2009. Victoria and Western Australia have seen a rise in HIV incidence from 2000 to 2006 (to a peak of 250 and 38 incident cases respectively), followed by a plateau to 2009. HIV incidence in the Northern Territory, Tasmania and Australian Capital Territory have increased since 2000; however, case numbers remain small (<20 per year). The estimated proportion of HIV infections not yet diagnosed to 2009 ranges from 10% (NSW) to 18% (Qld), with an average of 12% across Australia. Conclusions: HIV diagnosis trends among MSM in Australia reflect changes in estimated incidence to 2009, and reveal the largest increase in the past 10 years in Qld.

Could implementation of Australia's National Gay Men's Syphilis Action Plan have an indirect effect on the HIV epidemic?

Sexual Health ◽  
2012 ◽  
Vol 9 (2) ◽  
pp. 144 ◽  
Author(s):  
Alexander Hoare ◽  
Richard T. Gray ◽  
David P. Wilson
Keyword(s):  
Public Health ◽  
Gay Men ◽  
Indirect Effect ◽  
Hiv Transmission ◽  
Action Plan ◽  
Hiv Infections ◽  
Hiv Interventions ◽  
Sexually Transmissible Infections ◽  
Epidemiological Impact ◽  
Public Health Strategies

Objectives The number of incident infections of syphilis and HIV have increased over the past decade across Australia, particularly among gay men. In other industrialised settings, syphilis epidemics have also resurged coincidentally with increases in HIV diagnoses. Sexually transmissible infections (STI) are a biologically plausible cofactor for increasing HIV transmission. We pose the question: could strategies purely targeting syphilis also have an indirect impact on HIV incidence? Methods: We developed an agent-based computer model that simulates the transmission and disease progression of HIV and syphilis among a population of sexually active gay men, calibrated to reflect the epidemics in Victoria, Australia. The model was informed by detailed behavioural data from a variety of sources and was used to investigate the potential epidemiological impact of different public health interventions. Results: Assuming that syphilis could act as a biological cofactor for HIV transmission, from no effect to increasing risk by five-fold, our model indicates that if Australia’s syphilis action plan is effectively implemented then the number of HIV infections could decrease by up to 48% over the next decade in the absence of any specific HIV interventions. Conclusion: It is plausible that effective implementation of interventions targeting syphilis epidemics can have an indirect effect of mitigating the spread of HIV. The possible effects of STI should be considered in the design, implementation and evaluation of public health strategies and programs.

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