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Zhou S, Long N, Swanstrom R. Evolution Driven By A Varying Host Environment Selects For Distinct HIV-1 Entry Phenotypes and Other Informative Variants. FRONTIERS IN VIROLOGY (LAUSANNE, SWITZERLAND) 2023; 3:1291996. [PMID: 38239974 PMCID: PMC10795538 DOI: 10.3389/fviro.2023.1291996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2024]
Abstract
HIV-1 generates remarkable intra- and inter-host viral diversity during infection. In response to dynamic selective pressures of the host environment, HIV-1 will evolve distinct phenotypes - biological features that provide fitness advantages. The transmitted form of HIV-1 has been shown to require a high density of CD4 on the target cell surface (as found on CD4+ T cells) and typically uses CCR5 as a co-receptor during entry. This phenotype is referred to as R5 T cell-tropic (or R5 T-tropic); however, HIV-1 can switch to a secondary co-receptor, CXCR4, resulting in a X4 T cell-tropic phenotype. Macrophage-tropic (or M-tropic) HIV-1 can evolve to efficiently enter cells expressing low densities of CD4 on their surface (such as macrophages/microglia). So far only CCR5-using M-tropic viruses have been found. M-tropic HIV-1 is most frequently found within the central nervous system, and infection of the CNS has been associated with neurological impairment. It has been shown that interferon resistance phenotypes have a selective advantage during transmission, but the underlying mechanism of this is still unclear. During untreated infection, HIV-1 evolves under selective pressure from both the humoral/antibody response and CD8+ T cell killing. Sufficiently potent antiviral therapy will suppress viral replication, but if the antiviral drugs are not sufficiently potent to stop replication then the replicating virus will evolve drug resistance. HIV-1 phenotypes are highly relevant to treatment efforts, clinical outcomes, vaccine studies, and cure strategies. Therefore, it is critical to understand the dynamics of the host environment that drive these phenotypes and how they affect HIV-1 pathogenesis. This review will provide a comprehensive discussion of HIV-1 entry, transmission, and drug resistance phenotypes. Finally, we will assess the methods used in previous and current research to characterize these phenotypes.
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Affiliation(s)
- Shuntai Zhou
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Nathan Long
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ronald Swanstrom
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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2
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Jin X, Shi L, Wang C, Qiu T, Yin Y, Shen M, Fu G, Peng Z. Cost-effectiveness of oral pre-exposure prophylaxis and expanded antiretroviral therapy for preventing HIV infections in the presence of drug resistance among men who have sex with men in China: A mathematical modelling study. THE LANCET REGIONAL HEALTH - WESTERN PACIFIC 2022; 23:100462. [PMID: 35542892 PMCID: PMC9079770 DOI: 10.1016/j.lanwpc.2022.100462] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background Oral pre-exposure prophylaxis (PrEP) and antiretroviral therapy (ART) can effectively prevent HIV infections among men who have sex with men (MSM), but the emergence and transmission of HIV drug-resistance (HIVDR) may compromise their benefits. The costs and benefits of expanding PrEP and ART coverage in the presence of HIVDR in China remain unknown. Methods We developed a comprehensive dynamic transmission model incorporating the transmitted (TDR) and acquired (ADR) HIV drug resistance. The model was calibrated by the HIV surveillance data from 2009 to 2019 among MSM in Jiangsu Province, China, and validated by the dynamic prevalence of ADR and TDR. We aimed to investigate the impact of eight intervention scenarios (no PrEP, 20%, 50% or 80% of PrEP, without (77% coverage) or with (90% coverage) expanded ART) on the HIV epidemic trend and cost-effectiveness of PrEP over the next 30 years. Findings 20% or 50% PrEP + 90% ART would be cost-effective, with an incremental cost-effectiveness ratio (ICER) of 25,417 (95% confidence interval [CI]: 12,390–38,445) or 47,243 (23,756–70,729), and would yield 154,949 (89,662–220,237) or 179,456 (102,570–256,342) incremental quality-adjusted life-years (QALYs) over the next 30 years. No PrEP + 90% ART would yield 125,211 (73,448–176,974) incremental QALYs and be cost-saving. However, 20–80% PrEP + 77% ART and 80% PrEP + 90% ART with ICER of $77,862–$98,338 and $63,332, respectively, and were not cost-effective. A reduction of 64% in the annual cost of oral PrEP would make it highly cost-effective for 50% PrEP + 90% ART. Interpretation 20% or 50% PrEP + 90% ART is cost-effective for HIV control in the presence of HIVDR. Expanded ART alone may be the optimal policy under the current limited budgets. Funding National Natural Science Foundation of China, the National S&T Major Project Foundation of China.
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Guure C, Afagbedzi S, Torpey K. Willingness to take and ever use of pre-exposure prophylaxis among female sex workers in Ghana. Medicine (Baltimore) 2022; 101:e28798. [PMID: 35119051 PMCID: PMC8812709 DOI: 10.1097/md.0000000000028798] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 01/19/2022] [Indexed: 01/04/2023] Open
Abstract
Pre-exposure prophylaxis (PrEP) is a drug taken by people who are human immunodeficiency virus (HIV) negative and at increased risk of acquiring HIV. It's an effective intervention for HIV prevention. This study seeks to report on the prevalence and determinants of willingness to take and ever use of PrEP among female sex workers (FSW) in Ghana.The data analyzed was obtained from the Integrated Bio-behavioral Surveillance Survey conducted across the 16 regions of Ghana in 2020. Analysis was only performed on FSW who were tested negative to HIV and were sexually active. All included variables were described using medians, percentages, and graphs. Bayesian adjusted odds ratios and 95% credible intervals were estimated using a Bayesian generalized linear model via the binomial family of distributions under the logit link function.Of the 5107 FSW with complete data on willingness to use PrEP, 2737 (53.59%) reported their willingness to take PrEP. Out of the 998 respondents who have ever heard of PrEP only 64 (6.39%) have ever used PrEP. The median age of the respondents was 25 years. People with no comprehensive knowledge of HIV and acquired immunodeficiency syndrome as well as those who entered into the FSW business at age less than 25 years; 946 (34.56%) and 2181 (79.65%) respectively were more willing to take PrEP. FSW from 6 out of the 16 regions of Ghana have never used PrEP. A statistically significant difference between those who entered the sex work at age less than 25 years and those within 25 to 34 years was observed. About 23% of FSWs who had been screened for Sexually Transmitted Infections were more likely to take PrEP.Respondents with lesser age and no comprehensive knowledge of HIV were more willing to take PrEP. The willingness to accept PrEP among FSWs in Ghana is modest. However, utilization is low. Advocacy or intervention programs are required to improve uptake of PrEP.
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Affiliation(s)
- Chris Guure
- Department of Biostatistics, School of Public Health, University of Ghana, Legon-Accra, Ghana
| | - Seth Afagbedzi
- Department of Biostatistics, School of Public Health, University of Ghana, Legon-Accra, Ghana
| | - Kwasi Torpey
- Department of Population, Family and Reproductive Health, School of Public Health, University of Ghana, Legon-Accra, Ghana
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Wisutep P, Sirijatuphat R, Navanukroh O, Phatharodom P, Werarak P, Rattanasuwan W. Attitudes towards, knowledge about, and confidence to prescribe antiretroviral pre-exposure prophylaxis among healthcare providers in Thailand. Medicine (Baltimore) 2021; 100:e28120. [PMID: 34889271 PMCID: PMC8663816 DOI: 10.1097/md.0000000000028120] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 11/16/2021] [Indexed: 01/05/2023] Open
Abstract
HIV pre-exposure prophylaxis (HIV-PrEP) is an effective method for preventing HIV transmission, and it is recommended in several international guidelines. Perceptions and knowledge about HIV-PrEP prescription among healthcare providers have not been investigated in Thailand where HIV-PrEP is a novel healthcare topic. The objective of study was to determine healthcare providers' attitudes towards, knowledge about, and confidence to prescribe HIV-PrEP in Thailand.A questionnaire was administered to Thai healthcare providers during May 1, 2017 to September 5, 2018.Of the 500 questionnaires that were distributed, 460 were returned (92%). Respondents included 336 physicians (48 infectious disease [ID] physicians, 288 non-ID physicians) and 124 non-physicians (70 nurses, 35 pharmacists, and 19 others). Eighty one percent of respondents had a positive attitude towards HIV-PrEP. Multivariate analysis revealed being a non-ID physician, having prior knowledge about HIV-PrEP, believing that HIV-PrEP can reduce the number of new patients, and believing that HIV-PrEP is not associated with a higher incidence of other sexually transmitted infections were all factors significantly associated with having a positive attitude towards HIV-PrEP. The issue of most concern to respondents who had a negative attitude toward HIV-PrEP was poor patient adherence to antiviral medications. Only 57% of respondents had confidence to prescribe HIV-PrEP. Factors associated with confidence to prescribe HIV-PrEP included being an ID physician, believing that HIV-PrEP can reduce the number of new patients, believing in the safety of antiviral medications, and believing that HIV-PrEP is not associated with increased development of HIV drug resistance. The results of HIV-PrEP knowledge testing (8 questions) were categorized into good score (≥7/8) and fair score (≤6/8). Fifty five percent of participants had a good score result. Using multivariate analysis, the factors associated with a good score result were ID physician, having HIV-PrEP prescription experience, and believing that HIV-PrEP can reduce the number of new patients.Most Thai healthcare providers (81%) reported having a positive attitude towards HIV-PrEP. Successful HIV-PrEP implementation in Thailand will require steps to mitigate the described barriers, and training for healthcare providers, which will strengthen knowledge and improve both experience with and confidence to prescribe HIV-PrEP.
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Affiliation(s)
- Pruettichai Wisutep
- Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- School of Medicine, Institute of Medicine, Suranaree University of Technologgy, Nakornratchasima, Thailand
| | - Rujipas Sirijatuphat
- Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Oranich Navanukroh
- Department of Preventive and Social Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Phatharajit Phatharodom
- Department of Preventive and Social Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Peerawong Werarak
- Department of Preventive and Social Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Winai Rattanasuwan
- Department of Preventive and Social Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
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Okano JT, Sharp K, Valdano E, Palk L, Blower S. HIV transmission and source-sink dynamics in sub-Saharan Africa. Lancet HIV 2020; 7:e209-e214. [PMID: 32066532 DOI: 10.1016/s2352-3018(19)30407-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 10/17/2019] [Accepted: 10/31/2019] [Indexed: 12/01/2022]
Abstract
Multiple phylogenetic studies of HIV in sub-Saharan Africa have shown that mobility-driven transmission frequently occurs: many communities export and import strains. Mobility-driven transmission can result in source-sink dynamics: one community can sustain a micro-epidemic in another community in which transmission is too low to be self-sustaining. In epidemiology, the basic reproduction number (R0) is used to specify the sustainability threshold. R0 represents the average number of secondary infections generated by one infected individual in a community in which everyone is susceptible. If R0 is greater than 1, transmission is high enough to sustain an epidemic; if R0 is less than 1, it is not. Here, we discuss the conditions that are needed (in terms of R0) for source-sink transmission dynamics to occur in generalised HIV epidemics in sub-Saharan Africa, present an example of where these conditions could occur (ie, Namibia), and discuss the necessity of considering mobility-driven transmission when designing control strategies. Additionally, we discuss the need for a new generation of HIV transmission models that are more realistic than the current models. The new models should reflect not only geographical variation in epidemiology and demography, but also the spatial-temporal complexity of population-level movement patterns.
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Affiliation(s)
- Justin T Okano
- Center for Biomedical Modeling, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Katie Sharp
- Center for Biomedical Modeling, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Eugenio Valdano
- Center for Biomedical Modeling, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Laurence Palk
- Center for Biomedical Modeling, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Sally Blower
- Center for Biomedical Modeling, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
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Jewsbury S, Ward C. A case of M184V mutant human immunodeficiency virus in a patient using daily pre-exposure prophylaxis. Int J STD AIDS 2019; 31:85-87. [PMID: 31801029 DOI: 10.1177/0956462419879620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study presents a case report of a 31-year-old gay man who acquired human immunodeficiency virus while using daily emtricitabine (FTC)/tenofovir disoproxil fumarate (TDF) pre-exposure prophylaxis (PrEP). He had an M184V nucleoside reverse-transcriptase inhibitor mutation at diagnosis. Either he acquired a pre-existing M184V mutation or he acquired a wild-type virus but then suboptimal use of FTC/TDF led to the development of resistance. For PrEP to be safely managed and seroconvertors to be identified quickly, PrEP should be commissioned by the NHS and managed within sexual health clinics. Notwithstanding the current provision of PrEP, those accessing it must be reminded about the importance of regular testing and optimal adherence.
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Affiliation(s)
- Sally Jewsbury
- The Northern Contraception Sexual Health and HIV Service, Central Manchester NHS Foundation Trust, Manchester, UK
| | - Chris Ward
- The Northern Contraception Sexual Health and HIV Service, Central Manchester NHS Foundation Trust, Manchester, UK
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7
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Abstract
Clinical studies have demonstrated that use of tenofovir disoproxil fumarate with or without emtricitabine as antiretroviral pre-exposure prophylaxis (PrEP) can decrease the risk of human immunodeficiency virus (HIV) acquisition when medication adherence is high. However, the potential for PrEP to promote antiretroviral resistance remains an important public health consideration. We performed a search of the medical literature to identify studies that address HIV drug resistance during PrEP use. In this review, we summarize findings about emergent drug resistance during clinical trials of PrEP, case reports of seroconversions in patients adherent to PrEP, and animal studies of PrEP effectiveness against drug-resistant viral strains. We also discuss the potential utility of novel PrEP formulations for protection against drug-resistant HIV, the impact of drug resistance on HIV treatment options, and mathematical models that estimate the potential contribution of PrEP to population-level drug resistance. Evidence suggests that selection for HIV drug resistance with PrEP use is infrequent and most likely to occur when PrEP is used during undiagnosed acute HIV infection. Breakthrough infections during PrEP use with high adherence are possible, but appear to be rare. The prevalence of drug-resistant HIV strains needs to be monitored as PrEP is scaled up. However, the benefit of a decreased HIV incidence with wider PrEP use is likely to outweigh the risk of harms from possible increases in the prevalence of HIV drug resistance.
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Affiliation(s)
- Kevin M Gibas
- Division of Infectious Diseases, Beth Israel Deaconess Medical Center, 110 Francis St. W/LMOB, Suite GB, Boston, MA, 02215, USA
| | - Polly van den Berg
- Division of Infectious Diseases, Beth Israel Deaconess Medical Center, 110 Francis St. W/LMOB, Suite GB, Boston, MA, 02215, USA
| | - Victoria E Powell
- Division of Infectious Diseases, Beth Israel Deaconess Medical Center, 110 Francis St. W/LMOB, Suite GB, Boston, MA, 02215, USA
| | - Douglas S Krakower
- Division of Infectious Diseases, Beth Israel Deaconess Medical Center, 110 Francis St. W/LMOB, Suite GB, Boston, MA, 02215, USA.
- The Fenway Institute, Fenway Health, Boston, MA, USA.
- Department of Population Medicine, Harvard Medical School, Boston, MA, USA.
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8
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Niewiadomska AM, Jayabalasingham B, Seidman JC, Willem L, Grenfell B, Spiro D, Viboud C. Population-level mathematical modeling of antimicrobial resistance: a systematic review. BMC Med 2019; 17:81. [PMID: 31014341 PMCID: PMC6480522 DOI: 10.1186/s12916-019-1314-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/25/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Mathematical transmission models are increasingly used to guide public health interventions for infectious diseases, particularly in the context of emerging pathogens; however, the contribution of modeling to the growing issue of antimicrobial resistance (AMR) remains unclear. Here, we systematically evaluate publications on population-level transmission models of AMR over a recent period (2006-2016) to gauge the state of research and identify gaps warranting further work. METHODS We performed a systematic literature search of relevant databases to identify transmission studies of AMR in viral, bacterial, and parasitic disease systems. We analyzed the temporal, geographic, and subject matter trends, described the predominant medical and behavioral interventions studied, and identified central findings relating to key pathogens. RESULTS We identified 273 modeling studies; the majority of which (> 70%) focused on 5 infectious diseases (human immunodeficiency virus (HIV), influenza virus, Plasmodium falciparum (malaria), Mycobacterium tuberculosis (TB), and methicillin-resistant Staphylococcus aureus (MRSA)). AMR studies of influenza and nosocomial pathogens were mainly set in industrialized nations, while HIV, TB, and malaria studies were heavily skewed towards developing countries. The majority of articles focused on AMR exclusively in humans (89%), either in community (58%) or healthcare (27%) settings. Model systems were largely compartmental (76%) and deterministic (66%). Only 43% of models were calibrated against epidemiological data, and few were validated against out-of-sample datasets (14%). The interventions considered were primarily the impact of different drug regimens, hygiene and infection control measures, screening, and diagnostics, while few studies addressed de novo resistance, vaccination strategies, economic, or behavioral changes to reduce antibiotic use in humans and animals. CONCLUSIONS The AMR modeling literature concentrates on disease systems where resistance has been long-established, while few studies pro-actively address recent rise in resistance in new pathogens or explore upstream strategies to reduce overall antibiotic consumption. Notable gaps include research on emerging resistance in Enterobacteriaceae and Neisseria gonorrhoeae; AMR transmission at the animal-human interface, particularly in agricultural and veterinary settings; transmission between hospitals and the community; the role of environmental factors in AMR transmission; and the potential of vaccines to combat AMR.
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Affiliation(s)
- Anna Maria Niewiadomska
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, USA
| | - Bamini Jayabalasingham
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, USA.,Present Address: Elsevier Inc., 230 Park Ave, Suite B00, New York, NY, 10169, USA
| | - Jessica C Seidman
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, USA
| | | | - Bryan Grenfell
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, USA.,Princeton University, Princeton, NJ, USA
| | - David Spiro
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, USA
| | - Cecile Viboud
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, USA.
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Duwal S, Dickinson L, Khoo S, von Kleist M. Mechanistic framework predicts drug-class specific utility of antiretrovirals for HIV prophylaxis. PLoS Comput Biol 2019; 15:e1006740. [PMID: 30699105 PMCID: PMC6370240 DOI: 10.1371/journal.pcbi.1006740] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 02/11/2019] [Accepted: 12/20/2018] [Indexed: 11/21/2022] Open
Abstract
Currently, there is no effective vaccine to halt HIV transmission. However, pre-exposure prophylaxis (PrEP) with the drug combination Truvada can substantially decrease HIV transmission in individuals at risk. Despite its benefits, Truvada-based PrEP is expensive and needs to be taken once-daily, which often leads to inadequate adherence and incomplete protection. These deficits may be overcome by next-generation PrEP regimen, including currently investigated long-acting formulations, or patent-expired drugs. However, poor translatability of animal- and ex vivo/in vitro experiments, and the necessity to conduct long-term (several years) human trials involving considerable sample sizes (N>1000 individuals) are major obstacles to rationalize drug-candidate selection. We developed a prophylaxis modelling tool that mechanistically considers the mode-of-action of all available drugs. We used the tool to screen antivirals for their prophylactic utility and identify lower bound effective concentrations that can guide dose selection in PrEP trials. While in vitro measurable drug potency usually guides PrEP trial design, we found that it may over-predict PrEP potency for all drug classes except reverse transcriptase inhibitors. While most drugs displayed graded concentration-prophylaxis profiles, protease inhibitors tended to switch between none- and complete protection. While several treatment-approved drugs could be ruled out as PrEP candidates based on lack-of-prophylactic efficacy, darunavir, efavirenz, nevirapine, etravirine and rilpivirine could more potently prevent infection than existing PrEP regimen (Truvada). Notably, some drugs from this candidate set are patent-expired and currently neglected for PrEP repurposing. A next step is to further trim this candidate set by ruling out compounds with ominous safety profiles, to assess different administration schemes in silico and to test the remaining candidates in human trials. Pre-exposure prophylaxis (PrEP) is a novel, promising strategy to halt HIV transmission. PrEP with Truvada can substantially decrease the risk of infection. However, individuals often inadequately adhere to the once-daily regimen and the drug is expensive. These shortcomings may be overcome by next-generation PrEP compounds, including long-acting formulations. However, poor translatability of animal- and ex vivo/in vitro experiments, and difficulties in conducting long-term trials involving considerable sample sizes (N > 1000 individuals) make drug-candidate selection and optimization of administration schemes costly and often infeasible. We developed a simulation tool that mechanistically considers the mode-of-action of all antivirals. We used the tool to screen all available antivirals for their prophylactic utility and identified lower bound effective concentrations for designing PrEP dosing regimen in clinical trials. We found that in vitro measured drug potency may over-predict PrEP potency, for all antiviral classes except reverse transcriptase inhibitors. We could rule out a number of antivirals for PrEP repurposing and predicted that darunavir, efavirenz, nevirapine, etravirine and rilpivirine provide complete protection at clinically relevant concentrations. Further trimming of this candidate set by compound-safety and by assessing different implementation schemes is envisaged.
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Affiliation(s)
- Sulav Duwal
- Department of Mathematics & Computer Science, Freie Universität Berlin, Germany
- * E-mail: (SD); (MvK)
| | - Laura Dickinson
- Institute of Translational Medicine, University of Liverpool, United Kingdom
| | - Saye Khoo
- Institute of Translational Medicine, University of Liverpool, United Kingdom
| | - Max von Kleist
- Department of Mathematics & Computer Science, Freie Universität Berlin, Germany
- * E-mail: (SD); (MvK)
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10
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Milam J, Jain S, Dubé MP, Daar ES, Sun X, Corado K, Ellorin E, Blumenthal J, Haubrich R, Moore DJ, Morris SR. Sexual Risk Compensation in a Pre-exposure Prophylaxis Demonstration Study Among Individuals at Risk of HIV. J Acquir Immune Defic Syndr 2019; 80:e9-e13. [PMID: 30334877 PMCID: PMC6289757 DOI: 10.1097/qai.0000000000001885] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND A public health concern regarding HIV pre-exposure prophylaxis (PrEP) is sexual risk compensation (ie, increased unsafe sex among PrEP users that may undermine prevention efforts). METHODS This demonstration study (NCT#01761643; initiated in 2013) included 398 men who have sex with men who initiated PrEP and were followed over 48 weeks at 4 sites in Southern California. Wilcoxon signed-rank tests compared previous 30-day number of sex partners and condomless insertive anal sex and receptive anal sex (CIAS and CRAS, respectively) acts at weeks 4, 12, 24, 36, and 48 to baseline. At 2 sites, PrEP users were also compared with a lagged, comparison group of 99 men who have sex with men who did not receive PrEP over 24 weeks using linear regression models, adjusting for age, race/ethnicity, education, and respective baseline scores. Logistic regression compared week 24 sexually transmitted infection (STI) rates. RESULTS Over 48 weeks in the PrEP group, there were significant decreases in the number of unknown HIV status sex partners and increases in CRAS at all study visits; there was no consistent change in number of HIV+ sex partners or CIAS. Among participants at 2 sites, there were no significant differences between PrEP and non-PrEP users in change in number of partners, CIAS, CRAS, or STI rates at week 24. CONCLUSIONS Among early adopters of PrEP, there is some evidence for sexual risk compensation. Results support current guidelines of regular STI screening and behavioral risk reduction and adherence counseling with the provision of PrEP.
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Affiliation(s)
- Joel Milam
- Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Sonia Jain
- University of California, San Diego, San Diego, CA
| | - Michael P Dubé
- Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Eric S Daar
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA
- Long Beach Department of Health and Human Services, Long Beach, CA
- University of Colorado Denver, Denver, CO
| | - Xiaoying Sun
- University of California, San Diego, San Diego, CA
| | - Katya Corado
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA
| | - Eric Ellorin
- University of California, San Diego, San Diego, CA
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11
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de Waal R, Lessells R, Hauser A, Kouyos R, Davies MA, Egger M, Wandeler G. HIV drug resistance in sub-Saharan Africa: public health questions and the potential role of real-world data and mathematical modelling. J Virus Erad 2018; 4:55-58. [PMID: 30515315 PMCID: PMC6248850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The prevalence of pretreatment resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs) is >10% in many low-income countries. As a consequence, several sub-Saharan African countries have implemented, or are considering the introduction of, non-NNRTI-based first-line antiretroviral therapy (ART) for treatment-naïve and treatment-experienced patients. This is occurring at a time when ART programmes are expanding, in response to the World Health Organization guidelines, which recommend ART initiation regardless of CD4 cell count. Both those developments raise important questions regarding their potential impact on HIV drug resistance and the impact of HIV drug resistance on clinical outcomes. Those issues are particularly relevant to sub-Saharan Africa, where standardised ART regimens are used and where viral load monitoring and resistance testing are often not done routinely. It is therefore essential to forecast the impact of the implementation of universal ART, and the introduction of drugs such as dolutegravir to first-line regimens, on HIV drug resistance in order to inform future policies and to help ensure sustainable positive long-term outcomes. We discuss important public health considerations regarding HIV drug resistance, and describe how mathematical modelling, combined with real-world data from the four African Regions of the International epidemiology Databases to Evaluate AIDS consortium, could provide an early warning system for HIV drug resistance in sub-Saharan Africa.
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Affiliation(s)
- Reneé de Waal
- Centre for Infectious Disease Epidemiology and Research, School of Public Health and Family Medicine, University of Cape Town,
South Africa
| | - Richard Lessells
- KwaZulu-Natal Research Innovation and Sequencing Platform, Department of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal,
Durban,
South Africa
| | - Anthony Hauser
- Institute of Social and Preventive Medicine, University of Bern,
Switzerland
| | - Roger Kouyos
- Division of Infectious Diseases and Hospital Epidemiology, University of Zurich,
Switzerland
| | - Mary-Ann Davies
- Centre for Infectious Disease Epidemiology and Research, School of Public Health and Family Medicine, University of Cape Town,
South Africa
| | - Matthias Egger
- Centre for Infectious Disease Epidemiology and Research, School of Public Health and Family Medicine, University of Cape Town,
South Africa,Institute of Social and Preventive Medicine, University of Bern,
Switzerland
| | - Gilles Wandeler
- Corresponding author: Gilles Wandeler,
Department of Infectious Diseases,
Bern University Hospital,
Inselspital,
3010Bern,
Switzerland
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12
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de Waal R, Lessells R, Hauser A, Kouyos R, Davies MA, Egger M, Wandeler G. HIV drug resistance in sub-Saharan Africa: public health questions and the potential role of real-world data and mathematical modelling. J Virus Erad 2018. [DOI: 10.1016/s2055-6640(20)30347-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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13
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Palk L, Gerstoft J, Obel N, Blower S. A modeling study of the Danish HIV epidemic in men who have sex with men: travel, pre-exposure prophylaxis and elimination. Sci Rep 2018; 8:16003. [PMID: 30375426 PMCID: PMC6207710 DOI: 10.1038/s41598-018-33570-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 09/18/2018] [Indexed: 11/29/2022] Open
Abstract
UNAIDS has identified the Danish HIV epidemic in men who have sex with men (MSM) as a priority for elimination. Incidence is close to the elimination threshold of one new infection per year per 1,000 individuals. However, surveillance data show that HIV strains are being imported into Denmark, mainly due to travel. We use a transmission model to predict (from 2018 to 2030) the impact of pre-exposure prophylaxis (PrEP) on incidence. Our model reflects the current epidemic and diagnosis rates in the Danish MSM community. We conduct a sensitivity analysis based on 20,000 simulations, and assume that PrEP coverage could range from zero to 50% and diagnosis rates increase up to three-fold. We predict that incidence will fall below the elimination threshold, even without the introduction of PrEP, reaching 0.87 (median, 95% Confidence Interval: 0.65-1.23) new infections per 1,000 MSM by 2030. PrEP could reduce incidence to well below the threshold, if it results in a significant increase in diagnosis rates and reduces the number of infections occurring abroad. The Danish Medicine Agency and Danish Health Authority have recommended introducing PrEP. Our study provides strong support for this recommendation, and shows the importance of Danish MSM using PrEP when abroad.
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Affiliation(s)
- Laurence Palk
- Center for Biomedical Modeling, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, CA, 90024, USA
| | - Jan Gerstoft
- Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Niels Obel
- Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Sally Blower
- Center for Biomedical Modeling, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, CA, 90024, USA.
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14
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Shen M, Xiao Y, Rong L, Meyers LA, Bellan SE. The cost-effectiveness of oral HIV pre-exposure prophylaxis and early antiretroviral therapy in the presence of drug resistance among men who have sex with men in San Francisco. BMC Med 2018; 16:58. [PMID: 29688862 PMCID: PMC5914040 DOI: 10.1186/s12916-018-1047-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 03/28/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Poor adherence to either antiretroviral treatment (ART) or pre-exposure prophylaxis (PrEP) can promote drug resistance, though this risk is thought to be considerably higher for ART. In the population of men who have sex with men (MSM) in San Francisco, PrEP coverage reached 9.6% in 2014 and has continued to rise. Given the risk of drug resistance and high cost of second-line drugs, the costs and benefits of initiating ART earlier while expanding PrEP coverage remain unclear. METHODS We develop an infection-age-structured mathematical model and fit this model to the annual incidence of AIDS cases and deaths directly, and to resistance and demographic data indirectly. We investigate the impact of six various intervention scenarios (low, medium, or high PrEP coverage, with or without earlier ART) over the next 20 years. RESULTS Low (medium, high) PrEP coverage with earlier ART could prevent 22% (42%, 57%) of a projected 44,508 total new infections and 8% (26%, 41%) of a projected 18,426 new drug-resistant infections, and result in a gain of 43,649 (74,048, 103,270) QALYs over 20 years compared to the status quo, at a cost of $4745 ($78,811, $115,320) per QALY gained, respectively. CONCLUSIONS High PrEP coverage with earlier ART is expected to provide the greatest benefit but also entail the highest costs among the strategies considered. This strategy is cost-effective for the San Francisco MSM population, even considering the acquisition and transmission of ART-mediated drug resistance. However, without a substantial increase to San Francisco's annual HIV budget, the most advisable strategy may be initiating ART earlier, while maintaining current strategies of PrEP enrollment.
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Affiliation(s)
- Mingwang Shen
- Department of Epidemiology and Biostatistics, School of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, 710061, People's Republic of China.,School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an, 710049, People's Republic of China.,Department of Integrative Biology, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Yanni Xiao
- School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an, 710049, People's Republic of China.
| | - Libin Rong
- Department of Mathematics, University of Florida, Gainesville, FL, 32611, USA
| | - Lauren Ancel Meyers
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, 78712, USA.,The Santa Fe Institute, Santa Fe, NM, 87501, USA
| | - Steven E Bellan
- Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, GA, 30602, USA.,Center for Ecology of Infectious Diseases, University of Georgia, Athens, GA, 30602, USA
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15
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Zhukova A, Cutino-Moguel T, Gascuel O, Pillay D. The Role of Phylogenetics as a Tool to Predict the Spread of Resistance. J Infect Dis 2017; 216:S820-S823. [PMID: 29029155 DOI: 10.1093/infdis/jix411] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Drug resistance mutations emerge in genetic sequences of HIV through drug-selective pressure. Drug resistance can be transmitted. In this review we discuss phylogenetic methods used to study the emergence of drug resistance and the spread of resistant viruses.
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Affiliation(s)
- Anna Zhukova
- Unité Bioinformatique Evolutive, Centre de Bioinformatique, Biostatistique et Biologie Intégrative, C3BI USR 3756 Institut Pasteur et CNRS, France
| | | | - Olivier Gascuel
- Unité Bioinformatique Evolutive, Centre de Bioinformatique, Biostatistique et Biologie Intégrative, C3BI USR 3756 Institut Pasteur et CNRS, France
| | - Deenan Pillay
- Division of Infection and Immunity, University College London, United Kingdom.,Africa Health Research Institute, KwaZulu-Natal, South Africa
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16
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Robineau O, Velter A, Barin F, Boelle PY. HIV transmission and pre-exposure prophylaxis in a high risk MSM population: A simulation study of location-based selection of sexual partners. PLoS One 2017; 12:e0189002. [PMID: 29190784 PMCID: PMC5708822 DOI: 10.1371/journal.pone.0189002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Accepted: 11/16/2017] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVE In France, indications for pre-exposure prophylaxis (PrEP) for HIV prevention are based on individual-level risk factors for HIV infection. However, the risk of HIV infection may also depend on characteristics of sexual partnerships. Here we study how place-based selection of partners change transmission and the overall efficiency of PrEP. METHODS We used the PREVAGAY survey of sexual behavior and HIV serostatus in men who have sex with men (MSM) in a Parisian district to look for associations between sexual network characteristics and HIV infection. We then simulated HIV transmission in a high-risk MSM population. We used information about venues visited to meet casual sexual partners (clubs, backrooms or saunas) to define sexual networks. We then simulated HIV transmission in these networks and assessed the impact of PrEP in this population. RESULTS In the PREVAGAY study, we found that HIV serostatus changed with the type of venues visited, in addition to other individual risk factors. In simulations, we found similar differences in HIV incidence when the choice of venues visited was not random. The use of PrEP allowed reducing incidence, irrespective of the venues visited by PrEP users. However, with the same amount of PrEP, the number of infections adverted could almost double depending on network structure and venues visited by PrEP users. CONCLUSION This study shows that characteristics of the sexual network structure can strongly impact the effectiveness of PrEP interventions. These should be considered further to refine individual risk assessment and maximize the effect of individual-based prevention policies.
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Affiliation(s)
- Olivier Robineau
- Sorbonne Universités - Univ Paris 06, INSERM, Institut Pierre Louis d’Epidémiologie et de Santé Publique, INSERM U1136, Paris, France
- Service Universitaire des Maladies Infectieuses et du Voyageur, Centre Hospitalier Gustave Dron, Tourcoing, France
- Département des maladies infectieuses, Univ Lille 2, Lille, France
| | | | - Francis Barin
- Université François-Rabelais, INSERM UMR966, Tours, France
- Centre Hospitalier Régional Universitaire, Centre National de Référence du VIH, Tours, France
| | - Pierre-Yves Boelle
- Sorbonne Universités - Univ Paris 06, INSERM, Institut Pierre Louis d’Epidémiologie et de Santé Publique, INSERM U1136, Paris, France
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17
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Implementation and Operational Research: A Cost-Effective, Clinically Actionable Strategy for Targeting HIV Preexposure Prophylaxis to High-Risk Men Who Have Sex With Men. J Acquir Immune Defic Syndr 2017; 72:e61-7. [PMID: 26977749 DOI: 10.1097/qai.0000000000000987] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Preexposure prophylaxis (PrEP) is effective at preventing HIV infection among men who have sex with men (MSM), but there is uncertainty about how to identify high-risk MSM who should receive PrEP. METHODS We used a mathematical model to assess the cost-effectiveness of using the HIV Incidence Risk Index for MSM (HIRI-MSM) questionnaire to target PrEP to high-risk MSM. We simulated strategies of no PrEP, PrEP available to all MSM, and eligibility thresholds set to HIRI-MSM scores between 5 and 45, in increments of 5 (where a higher score predicts greater HIV risk). Based on the iPrEx, IPERGAY, and PROUD trials, we evaluated PrEP efficacies from 44% to 86% and annual costs from $5900 to 8700. We designate strategies with incremental cost-effectiveness ratio (ICER) ≤$100,000/quality-adjusted life-year (QALY) as "cost-effective." RESULTS Over 20 years, making PrEP available to all MSM is projected to prevent 33.5% of new HIV infections, with an ICER of $1,474,000/QALY. Increasing the HIRI-MSM score threshold reduces the prevented infections, but improves cost-effectiveness. A threshold score of 25 is projected to be optimal (most QALYs gained while still being cost-effective) over a wide range of realistic PrEP efficacies and costs. At low cost and high efficacy (IPERGAY), thresholds of 15 or 20 are optimal across a range of other input assumptions; at high cost and low efficacy (iPrEx), 25 or 30 are generally optimal. CONCLUSIONS The HIRI-MSM provides a clinically actionable means of guiding PrEP use. Using a score of 25 to determine PrEP eligibility could facilitate cost-effective use of PrEP among high-risk MSM who will benefit from it most.
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18
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Boydell N, Buston K, McDaid LM. Patterns of HIV testing practices among young gay and bisexual men living in Scotland: a qualitative study. BMC Public Health 2017; 17:660. [PMID: 28818055 PMCID: PMC5561622 DOI: 10.1186/s12889-017-4653-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 07/31/2017] [Indexed: 11/16/2022] Open
Abstract
Background Increasing overall rates, and frequency, of HIV testing in populations at risk is a key public health objective and a critical dimension of HIV prevention efforts. In the UK, men who have sex with men (MSM) remain one of the communities most at risk of HIV and, within this, young gay men are a key risk group. Understanding HIV testing practices is important in the development of interventions to promote testing among young gay and bisexual men. Methods Qualitative interviews were conducted with thirty young gay and bisexual men (aged 18–29) in Scotland. Thematic analysis of men’s accounts of their approach to HIV testing identified three overarching patterns of testing: ‘habitual’, ‘reactive’ and ‘ad hoc’. Results This qualitative study, the first to explore patterns of HIV testing practices among young gay and bisexual men in the UK, contributes novel findings around the role of social support and ‘community’ in shaping young men’s approaches to HIV testing. The findings suggest that social support can play an important role in encouraging and facilitating HIV testing among young gay men, however, social norms of non-testing also have the potential to act as a barrier to development of a regular routine. Men with habitual testing practices framed HIV testing as both a personal and ‘community’ responsibility, and more effective than testing in response to risk events or emergent symptoms. Men who reported reactive testing practices described testing for HIV primarily in response to perceived exposure to sexual risk, along with ‘transitional moments’ such as starting, ending or changes to a relationship. Among young men who reported testing on an ad hoc basis, inconvenience and disruptions to HIV testing practices, particularly where men lacked social support, acted as a barrier to developing a routine of regular testing. Conclusions Our findings suggest that interventions which seek to increase rates of HIV testing and testing frequency among young gay and bisexual men should include a specific focus on promoting and supporting positive testing practices within young men’s friendship groups and wider gay communities.
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Affiliation(s)
- Nicola Boydell
- Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, UK.
| | - Katie Buston
- MRC/CSO Social and Public Health Sciences Unit, University of Glasgow, Glasgow, UK
| | - Lisa Margaret McDaid
- MRC/CSO Social and Public Health Sciences Unit, University of Glasgow, Glasgow, UK
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19
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Shen M, Xiao Y, Rong L, Meyers LA, Bellan SE. Early antiretroviral therapy and potent second-line drugs could decrease HIV incidence of drug resistance. Proc Biol Sci 2017; 284:20170525. [PMID: 28659449 PMCID: PMC5489726 DOI: 10.1098/rspb.2017.0525] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/26/2017] [Indexed: 11/12/2022] Open
Abstract
Early initiation of antiretroviral therapy (ART) reduces the risk of drug-sensitive HIV transmission but may increase the transmission of drug-resistant HIV. We used a mathematical model to estimate the long-term population-level benefits of ART and determine the scenarios under which earlier ART (treatment at 1 year post-infection, on average) could decrease simultaneously both total and drug-resistant HIV incidence (new infections). We constructed an infection-age-structured mathematical model that tracked the transmission rates over the course of infection and modelled the patients' life expectancy as a function of ART initiation timing. We fitted this model to the annual AIDS incidence and death data directly, and to resistance data and demographic data indirectly among men who have sex with men (MSM) in San Francisco. Using counterfactual scenarios, we assessed the impact on total and drug-resistant HIV incidence of ART initiation timing, frequency of acquired drug resistance, and second-line drug effectiveness (defined as the combination of resistance monitoring, biomedical drug efficacy and adherence). Earlier ART initiation could decrease the number of both total and drug-resistant HIV incidence when second-line drug effectiveness is sufficiently high (greater than 80%), but increase the proportion of new infections that are drug resistant. Thus, resistance may paradoxically appear to be increasing while actually decreasing.
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Affiliation(s)
- Mingwang Shen
- School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Yanni Xiao
- School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Libin Rong
- Department of Mathematics and Statistics, Oakland University, Rochester, MI 48309, USA
- Department of Mathematics, University of Florida, Gainesville, FL 32611, USA
| | - Lauren Ancel Meyers
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA
- The Santa Fe Institute, Santa Fe, NM 87501, USA
| | - Steven E Bellan
- Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, GA 30602, USA
- Center for Ecology of Infectious Diseases, University of Georgia, Athens, GA 30602, USA
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20
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Blower S, Palk L. Methodological concerns regarding a PrEP model. THE LANCET. INFECTIOUS DISEASES 2017; 17:482. [PMID: 28447954 PMCID: PMC5748340 DOI: 10.1016/s1473-3099(17)30192-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 02/28/2017] [Indexed: 06/07/2023]
Affiliation(s)
- Sally Blower
- David Geffen School of Medicine, Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, CA 90095, USA.
| | - Laurence Palk
- David Geffen School of Medicine, Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, CA 90095, USA
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21
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22
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Zhao Y, Wood DT, Kojouharov HV, Kuang Y, Dimitrov DT. Impact of Population Recruitment on the HIV Epidemics and the Effectiveness of HIV Prevention Interventions. Bull Math Biol 2016; 78:2057-2090. [PMID: 27704329 DOI: 10.1007/s11538-016-0211-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 09/21/2016] [Indexed: 10/20/2022]
Abstract
Mechanistic mathematical models are increasingly used to evaluate the effectiveness of different interventions for HIV prevention and to inform public health decisions. By focusing exclusively on the impact of the interventions, the importance of the demographic processes in these studies is often underestimated. In this paper, we use simple deterministic models to assess the effectiveness of pre-exposure prophylaxis in reducing the HIV transmission and to explore the influence of the recruitment mechanisms on the epidemic and effectiveness projections. We employ three commonly used formulas that correspond to constant, proportional and logistic recruitment and compare the dynamical properties of the resulting models. Our analysis exposes substantial differences in the transient and asymptotic behavior of the models which result in 47 % variation in population size and more than 6 percentage points variation in HIV prevalence over 40 years between models using different recruitment mechanisms. We outline the strong influence of recruitment assumptions on the impact of HIV prevention interventions and conclude that detailed demographic data should be used to inform the integration of recruitment processes in the models before HIV prevention is considered.
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Affiliation(s)
- Yuqin Zhao
- School of Mathematics, University of Minnesota, Minneapolis, MN, USA
| | - Daniel T Wood
- Statistical Center for HIV/AIDS Research and Prevention (SCHARP), Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Hristo V Kojouharov
- Department of Mathematics, The University of Texas at Arlington, Arlington, TX, USA
| | - Yang Kuang
- Department of Mathematics and Statistics, Arizona State University, Tempe, AZ, USA
| | - Dobromir T Dimitrov
- Statistical Center for HIV/AIDS Research and Prevention (SCHARP), Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
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23
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Price JT, Wheeler SB, Stranix-Chibanda L, Hosek SG, Watts DH, Siberry GK, Spiegel HML, Stringer JS, Chi BH. Cost-Effectiveness of Pre-exposure HIV Prophylaxis During Pregnancy and Breastfeeding in Sub-Saharan Africa. J Acquir Immune Defic Syndr 2016; 72 Suppl 2:S145-53. [PMID: 27355502 PMCID: PMC5043081 DOI: 10.1097/qai.0000000000001063] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Antiretroviral pre-exposure prophylaxis (PrEP) for the prevention of HIV acquisition is cost-effective when delivered to those at substantial risk. Despite a high incidence of HIV infection among pregnant and breastfeeding women in sub-Saharan Africa (SSA), a theoretical increased risk of preterm birth on PrEP could outweigh the HIV prevention benefit. METHODS We developed a decision analytic model to evaluate a strategy of daily oral PrEP during pregnancy and breastfeeding in SSA. We approached the analysis from a health care system perspective across a lifetime time horizon. Model inputs were derived from existing literature and local sources. The incremental cost-effectiveness ratio (ICER) of PrEP versus no PrEP was calculated in 2015 U.S. dollars per disability-adjusted life year (DALY) averted. We evaluated the effect of uncertainty in baseline estimates through one-way and probabilistic sensitivity analyses. RESULTS PrEP administered to pregnant and breastfeeding women in SSA was cost-effective. In a base case of 10,000 women, the administration of PrEP averted 381 HIV infections but resulted in 779 more preterm births. PrEP was more costly per person ($450 versus $117), but resulted in fewer disability-adjusted life years (DALYs) (3.15 versus 3.49). The incremental cost-effectiveness ratio of $965/DALY averted was below the recommended regional threshold for cost-effectiveness of $6462/DALY. Probabilistic sensitivity analyses demonstrated robustness of the model. CONCLUSIONS Providing PrEP to pregnant and breastfeeding women in SSA is likely cost-effective, although more data are needed about adherence and safety. For populations at high risk of HIV acquisition, PrEP may be considered as part of a broader combination HIV prevention strategy.
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Affiliation(s)
- Joan T. Price
- Division of Global Women's Health, Department of Obstetrics and Gynecology, University of North Carolina Chapel Hill, Chapel Hill, NC
| | - Stephanie B. Wheeler
- Department of Health Policy and Management, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Lynda Stranix-Chibanda
- Department of Pediatrics and Child Health, College of Health Sciences, University of Zimbabwe, Harare, Zimbabwe
| | - Sybil G. Hosek
- Department of Psychiatry, John Stroger Hospital of Cook County, Chicago, IL
| | - D. Heather Watts
- Office of the Global AIDS Coordinator and Health Diplomacy, U.S. Department of State, Washington, DC
| | - George K. Siberry
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD; and
| | - Hans M. L. Spiegel
- Kelly Government Services, Contractor to Prevention Sciences Program, Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD
| | - Jeffrey S. Stringer
- Division of Global Women's Health, Department of Obstetrics and Gynecology, University of North Carolina Chapel Hill, Chapel Hill, NC
| | - Benjamin H. Chi
- Division of Global Women's Health, Department of Obstetrics and Gynecology, University of North Carolina Chapel Hill, Chapel Hill, NC
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24
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Fonner VA, Dalglish SL, Kennedy CE, Baggaley R, O’Reilly KR, Koechlin FM, Rodolph M, Hodges-Mameletzis I, Grant RM. Effectiveness and safety of oral HIV preexposure prophylaxis for all populations. AIDS 2016; 30:1973-83. [PMID: 27149090 PMCID: PMC4949005 DOI: 10.1097/qad.0000000000001145] [Citation(s) in RCA: 653] [Impact Index Per Article: 81.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/18/2016] [Accepted: 04/25/2016] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Preexposure prophylaxis (PrEP) offers a promising new approach to HIV prevention. This systematic review and meta-analysis evaluated the evidence for use of oral PrEP containing tenofovir disoproxil fumarate as an additional HIV prevention strategy in populations at substantial risk for HIV based on HIV acquisition, adverse events, drug resistance, sexual behavior, and reproductive health outcomes. DESIGN Rigorous systematic review and meta-analysis. METHODS A comprehensive search strategy reviewed three electronic databases and conference abstracts through April 2015. Pooled effect estimates were calculated using random-effects meta-analysis. RESULTS Eighteen studies were included, comprising data from 39 articles and six conference abstracts. Across populations and PrEP regimens, PrEP significantly reduced the risk of HIV acquisition compared with placebo. Trials with PrEP use more than 70% demonstrated the highest PrEP effectiveness (risk ratio = 0.30, 95% confidence interval: 0.21-0.45, P < 0.001) compared with placebo. Trials with low PrEP use did not show a significantly protective effect. Adverse events were similar between PrEP and placebo groups. More cases of drug-resistant HIV infection were found among PrEP users who initiated PrEP while acutely HIV-infected, but incidence of acquiring drug-resistant HIV during PrEP use was low. Studies consistently found no association between PrEP use and changes in sexual risk behavior. PrEP was not associated with increased pregnancy-related adverse events or hormonal contraception effectiveness. CONCLUSION PrEP is protective against HIV infection across populations, presents few significant safety risks, and there is no evidence of behavioral risk compensation. The effective and cost-effective use of PrEP will require development of best practices for fostering uptake and adherence among people at substantial HIV risk.
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Affiliation(s)
| | - Sarah L. Dalglish
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Caitlin E. Kennedy
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Rachel Baggaley
- HIV Department, World Health Organization, Geneva, Switzerland
| | - Kevin R. O’Reilly
- Medical University of South Carolina, Charleston, South Carolina, USA
| | | | | | | | - Robert M. Grant
- HIV Department, World Health Organization, Switzerland; Gladstone Institutes and the University of California; San Francisco AIDS Foundation, San Francisco, California, USA
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25
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Dimitrov DT, Boily MC, Hallett TB, Albert J, Boucher C, Mellors JW, Pillay D, van de Vijver DAMC. How Much Do We Know about Drug Resistance Due to PrEP Use? Analysis of Experts' Opinion and Its Influence on the Projected Public Health Impact. PLoS One 2016; 11:e0158620. [PMID: 27391094 PMCID: PMC4938235 DOI: 10.1371/journal.pone.0158620] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 06/20/2016] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Randomized controlled trials reported that pre-exposure prophylaxis (PrEP) with tenofovir and emtricitabine rarely selects for drug resistance. However, drug resistance due to PrEP is not completely understood. In daily practice, PrEP will not be used under the well-controlled conditions available in the trials, suggesting that widespread use of PrEP can result in increased drug resistance. METHODS We surveyed expert virologists with questions about biological assumptions regarding drug resistance due to PrEP use. The influence of these assumptions on the prevalence of drug resistance and the fraction of HIV transmitted resistance was studied with a mathematical model. For comparability, 50% PrEP-coverage of and 90% per-act efficacy of PrEP in preventing HIV acquisition are assumed in all simulations. RESULTS Virologists disagreed on the following: the time until resistance emergence (range: 20-180 days) in infected PrEP users with breakthrough HIV infections; the efficacy of PrEP against drug-resistant HIV (25%-90%); and the likelihood of resistance acquisition upon transmission (10%-75%). These differences translate into projections of 0.6%- 1% and 3.5%-6% infected individuals with detectable resistance 10 years after introducing PrEP, assuming 100% and 50% adherence, respectively. The rate of resistance emergence following breakthrough HIV infection and the rate of resistance reversion after PrEP use is discontinued, were the factors identified as most influential on the expected resistance associated with PrEP. Importantly, 17-23% infected individuals could virologically fail treatment as a result of past PrEP use or transmitted resistance to PrEP with moderate adherence. CONCLUSIONS There is no broad consensus on quantification of key biological processes that underpin the emergence of PrEP-associated drug resistance. Despite this, the contribution of PrEP use to the prevalence of the detectable drug resistance is expected to be small. However, individuals who become infected despite the use of PrEP should be closely monitored due to higher risk of virological failure when initiating antiretroviral treatment in the future.
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Affiliation(s)
- Dobromir T. Dimitrov
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Applied Mathematics, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| | - Marie-Claude Boily
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Timothy B. Hallett
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Jan Albert
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Charles Boucher
- Department of Virology, Erasmus Medical Centre, University Medical Centre Rotterdam, Rotterdam, Netherlands
| | - John W. Mellors
- Division of Infectious Diseases, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Deenan Pillay
- Research Department of Infection, University College Medical School, London, United Kingdom
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Sensitive sentinel mutation screening reveals differential underestimation of transmitted HIV drug resistance among demographic groups. AIDS 2016; 30:1439-45. [PMID: 26990626 DOI: 10.1097/qad.0000000000001099] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To examine the association of majority and minority-level transmitted HIV drug resistance (TDR) among diverse demographic populations in the United States and assess what different mutations may infer about TDR risk and engagement in care. DESIGN Used sensitive assays to screen 1070 deidentified convenience plasma specimens from United States national HIV surveillance conducted in 2009-2011 on newly diagnosed persons with no evidence of antiretroviral drug use. METHODS We applied validated allele-specific PCR for five HIV reverse transcriptase mutations as sentinel markers of TDR. The total and minority-level prevalence of TDR by demographic characteristics was compared. RESULTS Sensitive screening identified 72% more TDR than conventional sequencing for the five mutations assessed (13.6 vs. 7.9%, P < 0.0001), with K65R having the greatest increase (0-1.7%). One-third of K65R was in persons who also had at least one of the other mutations screened. The total TDR prevalence among whites (16.4%) and blacks (14.9%) was significantly higher than that among Hispanics/Latinos (6.4%) (P = 0.005 and 0.013, respectively). TDR prevalence was highest (23.1%) in those 13-19 years (85% black). TDR prevalence among women (72% black) was nearly as high as among MSM (47% black) (14.3 vs. 15.1%, respectively). CONCLUSION A significant proportion of TDR, primarily in older, white MSM, was undetected by conventional testing. The greatest underestimation was for rapid-decaying mutations typically associated with the source virus having recent exposure to antiretroviral therapy. However, total TDR prevalence was highest in the less than 20-year age group who were predominantly black, underscoring the importance of prevention efforts for at-risk youth.
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McDaid LM, Aghaizu A, Frankis J, Riddell J, Nardone A, Mercey D, Johnson AM, Hart GJ, Flowers P. Frequency of HIV testing among gay and bisexual men in the UK: implications for HIV prevention. HIV Med 2016; 17:683-93. [PMID: 26991460 PMCID: PMC5026165 DOI: 10.1111/hiv.12373] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2015] [Indexed: 11/29/2022]
Abstract
Objectives The aim of the study was to explore HIV testing frequency among UK men who have sex with men (MSM) in order to direct intervention development. Methods Cross‐sectional surveys were completed by 2409 MSM in Edinburgh, Glasgow and London in 2011 and a Scotland‐wide online survey was carried out in 2012/13. The frequency of HIV testing in the last 2 years was measured. Results Overall, 21.2% of respondents reported at least four HIV tests and 33.7% reported two or three tests in the last 2 years, so we estimate that 54.9% test annually. Men reporting at least four HIV tests were younger and less likely to be surveyed in London. They were more likely to report higher numbers of sexual and anal intercourse partners, but not “higher risk” unprotected anal intercourse (UAI) with at least two partners, casual partners and/or unknown/discordant status partners in the previous 12 months. Only 26.7% (238 of 893) of men reporting higher risk UAI reported at least four tests. Among all testers (n = 2009), 56.7% tested as part of a regular sexual health check and 35.5% tested following a risk event. Differences were observed between surveys, and those testing in response to a risk event were more likely to report higher risk UAI. Conclusions Guidelines recommend that all MSM test annually and those at “higher risk” test more frequently, but our findings suggest neither recommendation is being met. Additional efforts are required to increase testing frequency and harness the opportunities provided by biomedical HIV prevention. Regional, demographic and behavioural differences and variations in the risk profiles of testers suggest that it is unlikely that a “one size fits all” approach to increasing the frequency of testing will be successful.
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Affiliation(s)
- L M McDaid
- MRC/CSO Social and Public Health Sciences Unit, University of Glasgow, Glasgow, UK
| | | | - J Frankis
- Glasgow Caledonian University, Glasgow, UK
| | - J Riddell
- MRC/CSO Social and Public Health Sciences Unit, University of Glasgow, Glasgow, UK
| | | | - D Mercey
- University College London, London, UK
| | | | - G J Hart
- University College London, London, UK
| | - P Flowers
- Glasgow Caledonian University, Glasgow, UK
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Kunkel A, Colijn C, Lipsitch M, Cohen T. How could preventive therapy affect the prevalence of drug resistance? Causes and consequences. Philos Trans R Soc Lond B Biol Sci 2016; 370:20140306. [PMID: 25918446 PMCID: PMC4424438 DOI: 10.1098/rstb.2014.0306] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Various forms of preventive and prophylactic antimicrobial therapies have been proposed to combat HIV (e.g. pre-exposure prophylaxis), tuberculosis (e.g. isoniazid preventive therapy) and malaria (e.g. intermittent preventive treatment). However, the potential population-level effects of preventative therapy (PT) on the prevalence of drug resistance are not well understood. PT can directly affect the rate at which resistance is acquired among those receiving PT. It can also indirectly affect resistance by altering the rate at which resistance is acquired through treatment for active disease and by modifying the level of competition between transmission of drug-resistant and drug-sensitive pathogens. We propose a general mathematical model to explore the ways in which PT can affect the long-term prevalence of drug resistance. Depending on the relative contributions of these three mechanisms, we find that increasing the level of coverage of PT may result in increases, decreases or non-monotonic changes in the overall prevalence of drug resistance. These results demonstrate the complexity of the relationship between PT and drug resistance in the population. Care should be taken when predicting population-level changes in drug resistance from small pilot studies of PT or estimates based solely on its direct effects.
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Affiliation(s)
- Amber Kunkel
- Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA 02115, USA Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06520, USA
| | - Caroline Colijn
- Department of Mathematics, Imperial College, London SW7 2AZ, UK
| | - Marc Lipsitch
- Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA 02115, USA
| | - Ted Cohen
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06520, USA
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Mugwanya KK, Baeten JM. Safety of oral tenofovir disoproxil fumarate-based pre-exposure prophylaxis for HIV prevention. Expert Opin Drug Saf 2015; 15:265-73. [PMID: 26634852 DOI: 10.1517/14740338.2016.1128412] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Tenofovir disoproxil fumarate (TDF)-based pre-exposure prophylaxis is a novel HIV prevention strategy for individuals at increased sexual risk for HIV infection. For any biomedical prevention intervention, the bar for tolerating adverse effects in healthy persons is high compared to therapeutic interventions. AREAS COVERED We provide a concise summary of the clinical safety of TDF-based pre-exposure prophylaxis with focus on TDF-related effects on tolerability, kidney function, bone density, HIV resistance, sexual and reproductive health. The evidence base for this review is derived from a literature search of both randomized and observational studies evaluating efficacy and safety of TDF-based PrEP, TDF alone or in combination with emtricitabine, identified from PUBMED and EMBASE electronic databases, clinicaltrials.gov and major HIV conferences. EXPERT OPINION TDF-based pre-exposure prophylaxis is a potent intervention against HIV acquisition when taken which is generally safe and well tolerated. The risk of the small, non-progressive, and reversible decline in glomerular filtration rate and bone mineral density as well as the potential selection for drug resistance associated with PrEP are outweighed, at the population level and broadly for individuals, by PrEP's substantial reduction in the risk of HIV infection.
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Affiliation(s)
- Kenneth K Mugwanya
- a Department of Epidemiology , University of Washington , Seattle , WA , USA.,b Department of Global Health , University of Washington , Seattle , WA , USA.,c Division of Disease Control, School of Public Health , Makerere University , Kampala , Uganda
| | - Jared M Baeten
- a Department of Epidemiology , University of Washington , Seattle , WA , USA.,b Department of Global Health , University of Washington , Seattle , WA , USA.,d Department of Medicine , University of Washington , Seattle , WA , USA
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Burns DN, Grossman C, Turpin J, Elharrar V, Veronese F. Role of oral pre-exposure prophylaxis (PrEP) in current and future HIV prevention strategies. Curr HIV/AIDS Rep 2015; 11:393-403. [PMID: 25283184 DOI: 10.1007/s11904-014-0234-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Treatment as prevention is expected to have a major role in reducing HIV incidence, but other prevention interventions will also be required to bring the epidemic under control, particularly among key populations. One or more forms of pre-exposure prophylaxis (PrEP) will likely play a critical role. Oral PrEP with emtricitabine-tenofovir (Truvada®) is currently available in the US and some other countries, but uptake has been slow. We review the concerns that have contributed to this slow uptake and discuss current and future research in this critical area of HIV prevention research.
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Affiliation(s)
- David N Burns
- Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 5601 Fishers Lane, MSC 9831, Bethesda, MD, 20892, USA,
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Agniswamy J, Louis JM, Shen CH, Yashchuk S, Ghosh AK, Weber IT. Substituted Bis-THF Protease Inhibitors with Improved Potency against Highly Resistant Mature HIV-1 Protease PR20. J Med Chem 2015; 58:5088-95. [PMID: 26010498 DOI: 10.1021/acs.jmedchem.5b00474] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
An extremely drug resistant mutant of HIV-1 protease (PR) bearing 20 mutations (PR20) has been studied with two potent antiviral investigational inhibitors. GRL-5010A and GRL-4410A were designed to introduce hydrogen bond interactions with the flexible flaps of the PR by incorporating gem-difluorines and alkoxy, respectively, at the C4 position of the bis-THF of darunavir. PR20 provides an excellent model for high level resistance, since clinical inhibitors are >1000-fold less active on PR20 than on wild-type enzyme. GRL-5010A and GRL-4410A show inhibition constants of 4.3 ± 7.0 and 1.7 ± 1.8 nM, respectively, for PR20, compared to the binding affinity of 41 ± 1 nM measured for darunavir. Crystal structures of PR20 in complexes with the two inhibitors confirmed the new hydrogen bond interactions with Gly 48 in the flap of the enzyme. The two new compounds are more effective than darunavir in inhibiting mature PR20 and show promise for further development of antiviral agents targeting highly resistant PR mutants.
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Affiliation(s)
- Johnson Agniswamy
- †Department of Biology, Molecular Basis of Disease Program, Georgia State University, Atlanta, Georgia 30303, United States
| | - John M Louis
- ‡Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, DHHS, Bethesda, Maryland 20892-0520, United States
| | - Chen-Hsiang Shen
- †Department of Biology, Molecular Basis of Disease Program, Georgia State University, Atlanta, Georgia 30303, United States
| | - Sofiya Yashchuk
- §Department of Chemistry and Medicinal Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Arun K Ghosh
- §Department of Chemistry and Medicinal Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Irene T Weber
- †Department of Biology, Molecular Basis of Disease Program, Georgia State University, Atlanta, Georgia 30303, United States
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32
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Cahill SR, Mayer KH, Boswell SL. The Ryan White HIV/AIDS Program in the Age of Health Care Reform. Am J Public Health 2015; 105:1078-85. [PMID: 25880940 PMCID: PMC4431102 DOI: 10.2105/ajph.2014.302442] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2014] [Indexed: 01/22/2023]
Abstract
Thanks to the Affordable Care Act, thousands of people living with HIV who have received Ryan White HIV/AIDS Program-funded care are now eligible for Medicaid or subsidized insurance. The protection against insurance discrimination on the basis of preexisting conditions is increasing health care access for many, but this does not mean that the Ryan White Program is no longer needed. Services essential to improving outcomes on the continuum of HIV care are not supported by any other source. Because of the growing number of people living with HIV, we must increase funding for the Ryan White Program and increase the number of HIV care providers.
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Affiliation(s)
- Sean R Cahill
- Sean R. Cahill is with the Fenway Institute, Fenway Health, Boston, MA and the Wagner School of Public Service, New York University, New York. Kenneth H. Mayer is with the Fenway Institute, Fenway Health and the Beth Israel Deaconess Medical Center, Boston, MA. Stephen L. Boswell is with the Fenway Institute, Fenway Health and the Department of Medicine, Harvard Medical School, Boston, MA
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33
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Carnegie NB, Goodreau SM, Liu A, Vittinghoff E, Sanchez J, Lama JR, Buchbinder S. Targeting pre-exposure prophylaxis among men who have sex with men in the United States and Peru: partnership types, contact rates, and sexual role. J Acquir Immune Defic Syndr 2015; 69:119-25. [PMID: 25942463 PMCID: PMC4422184 DOI: 10.1097/qai.0000000000000555] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND We aim to identify optimal strategies for deploying pre-exposure prophylaxis among men who have sex with men (MSM) in the United States and Peru to maximize population-level effectiveness in an efficient manner. We use epidemic models to simulate the impact of targeting strategies. Most studies have focused on targeting either the general population or high-risk MSM. Alternative strategies, including serodiscordant couples, may better balance effectiveness and efficiency. METHODS We use dynamic stochastic sexual network models based on exponential-family random graph modeling, parameterized from behavioral surveys of MSM in the United States and Peru. These models represent main partnerships and casual contacts separately, permitting modeling of interventions targeting men whose risk derives from combinations of relational types. We also model varying rates of uptake and adherence to pre-exposure prophylaxis (PrEP). We assess sensitivity of results to risk compensation through increases in condomless casual contacts and condomless sex in main partnerships. RESULTS Targeting all men who are not exclusively insertive has the largest impact on HIV incidence, but targeting only those with high levels of casual activity yields comparable results using fewer person-years on PrEP. The effect is robust to risk compensation in the United States, but less so in Peru. Targeting serodiscordant main partnerships does not significantly impact incidence, but requires fewer person-years on PrEP per infection averted than other strategies. CONCLUSIONS PrEP could be effective in reducing new infections at the population level in both settings. Serodiscordant partnerships are an attractive component of a targeting program, but targeting should include other high-risk men.
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Affiliation(s)
| | | | - Albert Liu
- San Francisco Department of Public Health
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Buchbinder SP, Liu AY. CROI 2015: Advances in HIV Testing and Prevention Strategies. TOPICS IN ANTIVIRAL MEDICINE 2015; 23:8-27. [PMID: 25965309 PMCID: PMC6148903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 03/11/2015] [Indexed: 06/04/2023]
Abstract
HIV testing rates and awareness of HIV serostatus have improved globally, but disparities continue between black and white men who have sex with men (MSM) in the United States, and between women and men globally. The 2015 Conference on Retroviruses and Opportunistic Infections (CROI) was a watershed moment for preexposure prophylaxis (PrEP). Two efficacy trials conducted in MSM were stopped early because of an 86% reduction in the risk of HIV acquisition among men taking tenofovir and emtricitabine. New drugs, long-acting formulations, and different patterns of dosing are undergoing evaluation. Poor adherence has limited PrEP effectiveness in some populations, and new measures of drug levels in dried blood spots and hair appear to be promising new tools. Pharmacokinetic differences of PrEP agents in rectal versus vaginal tissue preclude extrapolating PrEP trial results among MSM to women. Several studies reported no HIV transmissions between HIV-serodiscordant couples when the seropositive partner was successfully treated for 6 months. However, consistent viral suppression does not occur in a substantial minority of patients in many clinics, reducing the potential impact of treatment as prevention.
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Affiliation(s)
- Susan P Buchbinder
- University of California San Francisco and San Francisco Department of Public Health, San Francisco, CA, USA
| | - Albert Y Liu
- University of California San Francisco and San Francisco Department of Public Health, San Francisco, CA, USA
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35
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Grant RM, Liegler T. Weighing the risk of drug resistance with the benefits of HIV preexposure prophylaxis. J Infect Dis 2015; 211:1202-4. [PMID: 25587019 PMCID: PMC4371769 DOI: 10.1093/infdis/jiu678] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Robert M Grant
- Gladstone Institutes University of California-San Francisco San Francisco AIDS Foundation, California
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36
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HIV treatment as prevention: contradictory perspectives from dynamic mathematical models. ScientificWorldJournal 2014; 2014:760734. [PMID: 25580461 PMCID: PMC4279253 DOI: 10.1155/2014/760734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Accepted: 11/26/2014] [Indexed: 12/20/2022] Open
Abstract
The preventative effects of antiretroviral therapy for people with HIV have been debated since they were first raised. Models commenced studying the preventive effects of treatment in the 1990s, prior to initial public reports. However, the outcomes of the preventive effects of antiretroviral use were not consistent. Some outcomes of dynamic models were based on unfeasible assumptions, such as no consideration of drug resistance, behavior disinhibition, or economic inputs in poor countries, and unrealistic input variables, for example, overstated initiation time, adherence, coverage, and efficacy of treatment. This paper reviewed dynamic mathematical models to ascertain the complex effects of ART on HIV transmission. This review discusses more conservative inputs and outcomes relative to antiretroviral use in HIV infections in dynamic mathematical models. ART alone cannot eliminate HIV transmission.
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Gerberry DJ, Wagner BG, Garcia-Lerma JG, Heneine W, Blower S. Using geospatial modelling to optimize the rollout of antiretroviral-based pre-exposure HIV interventions in Sub-Saharan Africa. Nat Commun 2014; 5:5454. [PMID: 25462707 PMCID: PMC4322933 DOI: 10.1038/ncomms6454] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 10/02/2014] [Indexed: 11/18/2022] Open
Abstract
Antiretroviral-based pre-exposure HIV interventions may soon be rolled out in resource-constrained Sub-Saharan African countries, but rollout plans have yet to be designed. Here we use geospatial modeling and optimization techniques to compare two rollout plans for ARV-based microbicides in South Africa: a utilitarian plan that minimizes incidence by using geographic targeting, and an egalitarian plan that maximizes geographic equity in access to interventions. We find significant geographic variation in the efficiency of interventions in reducing HIV transmission, and that efficiency increases disproportionately with increasing incidence. The utilitarian plan would result in considerable geographic inequity in access to interventions, but (by exploiting geographic variation in incidence) could prevent ~40% more infections than the egalitarian plan. Our results show that the geographic resource allocation decisions made at the beginning of a rollout, and the location where the rollout is initiated, will be crucial in determining the success of interventions in reducing HIV epidemics.
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Affiliation(s)
- David J Gerberry
- Center for Biomedical Modeling, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, California 90024, USA
| | - Bradley G Wagner
- Center for Biomedical Modeling, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, California 90024, USA
| | - J Gerardo Garcia-Lerma
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia 30329, USA
| | - Walid Heneine
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia 30329, USA
| | - Sally Blower
- Center for Biomedical Modeling, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, California 90024, USA
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Emerging antiretroviral drug resistance in sub-Saharan Africa: novel affordable technologies are needed to provide resistance testing for individual and public health benefits. AIDS 2014; 28:2643-8. [PMID: 25493592 DOI: 10.1097/qad.0000000000000502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Kim SW, Pulkki-Brannstrom AM, Skordis-Worrall J. Comparing the cost effectiveness of harm reduction strategies: a case study of the Ukraine. COST EFFECTIVENESS AND RESOURCE ALLOCATION 2014; 12:25. [PMID: 25873788 PMCID: PMC4396789 DOI: 10.1186/1478-7547-12-25] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 11/17/2014] [Indexed: 11/25/2022] Open
Abstract
Background Harm reduction strategies commonly include needle and syringe programmes (NSP), opioid substitution therapy (OST) and interventions combining these two strategies. Despite the proven effectiveness of harm-reduction strategies in reducing human immunodeficiency virus (HIV) infection among injecting drug users (IDUs), no study has compared the cost-effectiveness of these interventions, nor the incremental cost effectiveness of combined therapy. Using data from the Global Fund, this study compares the cost-effectiveness of harm reduction strategies in Eastern Europe and Central Asia, using the Ukraine as a case study. Methods A Markov Monte Carlo simulation is carried out using parameters from the literature and cost data from the Global Fund. Effectiveness is presented as both QALYs and infections averted. Costs are measured in 2011 US dollars. Results The Markov Monte Carlo simulation estimates the cost-effectiveness ratio per infection averted as $487.4 [95% CI: 488.47-486.35] in NSP and $1145.9 [95% CI: 1143.39-1148.43] in OST. Combined intervention is more costly but more effective than the alternative strategies with a cost effectiveness ratio of $851.6[95% CI: 849.82-853.55]. The ICER of the combined strategy is $1086.9/QALY [95% CI: 1077.76:1096.24] compared with NSP, and $461.0/infection averted [95% CI: 452.98:469.04] compared with OST. These results are consistent with previous studies. Conclusions Despite the inherent limitations of retrospective data, this study provides evidence that harm-reduction interventions are a cost-effective way to reduce HIV prevalence. More research on into cost effectiveness in different settings, and the availability of fiscal space for government uptake of programmes, is required.
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Affiliation(s)
- Sung Wook Kim
- UCL Institute for Global Health, 30 Guilford Street, London, WC1N 1EH UK
| | - Anni-Maria Pulkki-Brannstrom
- UCL Institute for Global Health, 30 Guilford Street, London, WC1N 1EH UK ; Epidemiology and Global Health Department, Umeå University, Umea, Sweden
| | - Jolene Skordis-Worrall
- UCL Institute for Global Health, 30 Guilford Street, London, WC1N 1EH UK ; London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT UK
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How can we get close to zero? The potential contribution of biomedical prevention and the investment framework towards an effective response to HIV. PLoS One 2014; 9:e111956. [PMID: 25372770 PMCID: PMC4221192 DOI: 10.1371/journal.pone.0111956] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 09/23/2014] [Indexed: 12/16/2022] Open
Abstract
Background In 2011 an Investment Framework was proposed that described how the scale-up of key HIV interventions could dramatically reduce new HIV infections and deaths in low and middle income countries by 2015. This framework included ambitious coverage goals for prevention and treatment services resulting in a reduction of new HIV infections by more than half. However, it also estimated a leveling in the number of new infections at about 1 million annually after 2015. Methods We modeled how the response to AIDS can be further expanded by scaling up antiretroviral treatment (ART) within the framework provided by the 2013 WHO treatment guidelines. We further explored the potential contributions of new prevention technologies: ‘Test and Treat’, pre-exposure prophylaxis and an HIV vaccine. Findings Immediate aggressive scale up of existing approaches including the 2013 WHO guidelines could reduce new infections by 80%. A ‘Test and Treat’ approach could further reduce new infections. This could be further enhanced by a future highly effective pre-exposure prophylaxis and an HIV vaccine, so that a combination of all four approaches could reduce new infections to as low as 80,000 per year by 2050 and annual AIDS deaths to 260,000. Interpretation In a set of ambitious scenarios, we find that immediate implementation of the 2013 WHO antiretroviral therapy guidelines could reduce new HIV infections by 80%. Further reductions may be achieved by moving to a ‘Test and Treat’ approach, and eventually by adding a highly effective pre-exposure prophylaxis and an HIV vaccine, if they become available.
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McMahon JM, Myers JE, Kurth AE, Cohen SE, Mannheimer SB, Simmons J, Pouget ER, Trabold N, Haberer JE. Oral pre-exposure prophylaxis (PrEP) for prevention of HIV in serodiscordant heterosexual couples in the United States: opportunities and challenges. AIDS Patient Care STDS 2014; 28:462-74. [PMID: 25045996 PMCID: PMC4135325 DOI: 10.1089/apc.2013.0302] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Oral HIV pre-exposure prophylaxis (PrEP) is a promising new biomedical prevention approach in which HIV-negative individuals are provided with daily oral antiretroviral medication for the primary prevention of HIV-1. Several clinical trials have demonstrated efficacy of oral PrEP for HIV prevention among groups at high risk for HIV, with adherence closely associated with level of risk reduction. In the United States (US), three groups have been prioritized for initial implementation of PrEP-injection drug users, men who have sex with men at substantial risk for HIV, and HIV-negative partners within serodiscordant heterosexual couples. Numerous demonstration projects involving PrEP implementation among MSM are underway, but relatively little research has been devoted to study PrEP implementation in HIV-serodiscordant heterosexual couples in the US. Such couples face a unique set of challenges to PrEP implementation at the individual, couple, and provider level with regard to PrEP uptake and maintenance, adherence, safety and toxicity, clinical monitoring, and sexual risk behavior. Oral PrEP also provides new opportunities for serodiscordant couples and healthcare providers for primary prevention and reproductive health. This article provides a review of the critical issues, challenges, and opportunities involved in the implementation of oral PrEP among HIV-serodiscordant heterosexual couples in the US.
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Affiliation(s)
- James M. McMahon
- School of Nursing, University of Rochester Medical Center, Rochester, New York
| | - Julie E. Myers
- Bureau of HIV/AIDS Prevention and Control, New York City Department of Health and Mental Hygiene, New York, New York
- Division of Infectious Diseases, Department of Medicine, Columbia University, New York, New York
| | - Ann E. Kurth
- College of Nursing, New York University, New York, New York
| | - Stephanie E. Cohen
- San Francisco Department of Public Health, STD Prevention and Control, San Francisco, California
| | - Sharon B. Mannheimer
- Department of Medicine, Harlem Hospital, Columbia University College of Physicians and Surgeons, New York, New York
| | - Janie Simmons
- National Development and Research Institutes, New York, New York
| | | | - Nicole Trabold
- School of Nursing, University of Rochester Medical Center, Rochester, New York
| | - Jessica E. Haberer
- Massachusetts General Hospital Center for Global Health and Harvard Medical School, Boston, Massachusetts
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Sharma M, Wilton J, Senn H, Fowler S, Tan DHS. Preparing for PrEP: perceptions and readiness of canadian physicians for the implementation of HIV pre-exposure prophylaxis. PLoS One 2014; 9:e105283. [PMID: 25133648 PMCID: PMC4136811 DOI: 10.1371/journal.pone.0105283] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 07/22/2014] [Indexed: 12/04/2022] Open
Abstract
Recent evidence has demonstrated the efficacy of pre-exposure prophylaxis (PrEP) for HIV prevention, but concerns persist around its use. Little is known about Canadian physicians' knowledge of and willingness to prescribe PrEP. We disseminated an online survey to Canadian family, infectious disease, internal medicine, and public health physicians between September 2012-June 2013 to determine willingness to prescribe PrEP. Criteria for analysis were met by 86 surveys. 45.9% of participants felt "very familiar" with PrEP, 49.4% felt that PrEP should be approved by Health Canada, and 45.4% of respondents were willing to prescribe PrEP. Self-identifying as an HIV expert (odds ratio, OR = 4.1, 95% confidence interval, CI = 1.6-10.2), familiarity with PrEP (OR = 5.0, 95%CI = 1.3-19.0) and having been asked by patients about PrEP (OR = 4.0, 95%CI = 1.5-10.5) were positively associated with willingness to prescribe PrEP on univariable analysis. The latter two were the strongest predictors on multivariate analysis. Participants cited cost and efficacy as major concerns. 75.3% did not feel that information had been adequately disseminated among physicians. In summary, Canadian physicians demonstrate varying levels of support for PrEP and express concerns about its implementation. Further research on real-world effectiveness, continuing medical education, and clinical support is needed to prepare physicians for this prevention strategy.
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Affiliation(s)
- Malika Sharma
- Division of Infectious Diseases, University of Toronto, Toronto, Ontario, Canada
| | - James Wilton
- Canadian AIDS Treatment Information Exchange, Toronto, Ontario, Canada
| | - Heather Senn
- Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | | | - Darrell H. S. Tan
- Division of Infectious Diseases, University of Toronto, Toronto, Ontario, Canada
- Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Hassle Free Clinic, Toronto, Ontario, Canada
- Division of Infectious Diseases, St Michael's Hospital, Toronto, Ontario, Canada
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Dimitrov D, Kuang Y, Mâsse BR. Assessing the Public Health impact of HIV interventions: the critical role of demographics. J Acquir Immune Defic Syndr 2014; 66:e60-2. [PMID: 24828270 PMCID: PMC4053692 DOI: 10.1097/qai.0000000000000133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Dobromir Dimitrov
- *Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA †Department of Applied Mathematics, University of Washington, Seattle, WA ‡School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ §Department of Mathematics, King Abdulaziz University, Jeddah, Saudi Arabia ‖CHU Sainte-Justine Research Centre, University of Montreal, Montreal, Quebec, Canada
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Wade Taylor S, Mayer KH, Elsesser SM, Mimiaga MJ, O'Cleirigh C, Safren SA. Optimizing content for pre-exposure prophylaxis (PrEP) counseling for men who have sex with men: Perspectives of PrEP users and high-risk PrEP naïve men. AIDS Behav 2014; 18:871-9. [PMID: 24077928 DOI: 10.1007/s10461-013-0617-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Existing trials of antiretroviral (ARV) medication as chemoprophylaxis against HIV reveal that the degree of protection is primarily dependent on product adherence. However, there is a lack of data on targets for behavioral interventions to improve adherence to ARV as prevention. Information from individuals who have used ARV as pre-exposure prophylaxis (PrEP) can inform behavioral intervention development. Thirty-nine HIV-uninfected MSM at high risk for HIV acquisition participated in one of four semi-structured focus groups. Two of the focus groups consisted of MSM who had been prescribed and used PrEP in the context of a clinical trial; the other two consisted of high-risk MSM who had not previously used PrEP. An in-depth, within-case/across-case content analysis resulted in six descriptive themes potentially salient for a PrEP adherence behavioral intervention: (1) motivations to use PrEP, (2) barriers to PrEP use, (3) facilitators to PrEP use, (4) sexual decision-making in the context of PrEP, (5) prospective PrEP education content, and, (6) perceived effective characteristics of PrEP delivery personnel. Addressing these themes in behavioral interventions in the context of prescribing PrEP may result in the optimal "packaging" public health programs that implement PrEP for high-risk MSM.
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Lou J, Blevins M, Ruan Y, Vermund SH, Tang S, Webb GF, Shepherd BE, He X, Lu H, Shao Y, Qian HZ. Modeling the impact on HIV incidence of combination prevention strategies among men who have sex with men in Beijing, China. PLoS One 2014; 9:e90985. [PMID: 24626165 PMCID: PMC3953201 DOI: 10.1371/journal.pone.0090985] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 02/05/2014] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE To project the HIV/AIDS epidemics among men who have sex with men (MSM) under different combinations of HIV testing and linkage to care (TLC) interventions including antiretroviral therapy (ART) in Beijing, China. DESIGN Mathematical modeling. METHODS Using a mathematical model to fit prevalence estimates from 2000-2010, we projected trends in HIV prevalence and incidence during 2011-2020 under five scenarios: (S1) current intervention levels by averaging 2000-2010 coverage; (S2) increased ART coverage with current TLC; (S3) increased TLC/ART coverage; (S4) increased condom use; and (S5) increased TLC/ART plus increased condom use. RESULTS The basic reproduction number based upon the current level of interventions is significantly higher than 1 (R0 = 2.09; 95% confidence interval (CI), 1.83-2.35), suggesting that the HIV epidemic will continue to increase to 2020. Compared to the 2010 prevalence of 7.8%, the projected HIV prevalence in 2020 for the five prevention scenarios will be: (S1) Current coverage: 21.4% (95% CI, 9.9-31.7%); (S2) Increased ART: 19.9% (95% CI, 9.9-28.4%); (S3) Increased TLC/ART: 14.5% (95% CI, 7.0-23.8%); (S4) Increased condom use: 13.0% (95% CI, 9.8-28.4%); and (S5) Increased TLC/ART and condom use: 8.7% (95% CI, 5.4-11.5%). HIV epidemic will continue to rise (R0 > 1) for S1-S4 even with hyperbolic coverage in the sensitivity analysis, and is expected to decline (R0 = 0.93) for S5. CONCLUSION Our transmission model suggests that Beijing MSM will have a rapidly rising HIV epidemic. Even enhanced levels of TLC/ART will not interrupt epidemic expansion, despite optimistic assumptions for coverage. Promoting condom use is a crucial component of combination interventions.
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Affiliation(s)
- Jie Lou
- Department of Mathematics, Shanghai University, Shanghai, China
| | - Meridith Blevins
- Vanderbilt Institute for Global Health, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Biostatistics, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Yuhua Ruan
- State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing, China
| | - Sten H. Vermund
- Vanderbilt Institute for Global Health, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Sanyi Tang
- College of Mathematics and Information Science, Shaanxi Normal University, Xi'an, Shaanxi Province, China
| | - Glenn F. Webb
- Department of Mathematics, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Bryan E. Shepherd
- Vanderbilt Institute for Global Health, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Biostatistics, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Xiong He
- Institute for AIDS/STD Prevention & Control, Beijing Municipal Center for Disease Control and Prevention, Beijing, China
| | - Hongyan Lu
- Institute for AIDS/STD Prevention & Control, Beijing Municipal Center for Disease Control and Prevention, Beijing, China
| | - Yiming Shao
- State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing, China
| | - Han-Zhu Qian
- Vanderbilt Institute for Global Health, Vanderbilt University, Nashville, Tennessee, United States of America
- Division of Epidemiology, Department of Medicine, Vanderbilt University, Nashville, Tennessee, United States of America
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Smith J, Nyamukapa C, Gregson S, Lewis J, Magutshwa S, Schumacher C, Mushati P, Hallett T, Garnett G. The distribution of sex acts and condom use within partnerships in a rural sub-Saharan African population. PLoS One 2014; 9:e88378. [PMID: 24558387 PMCID: PMC3928170 DOI: 10.1371/journal.pone.0088378] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 01/07/2014] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION In an HIV/AIDS epidemic driven primarily by heterosexual transmission, it is important to have an understanding of the human sexual behaviour patterns that influence transmission. We analysed the distribution and predictors of within-partnership sexual behaviour and condom use in rural Zimbabwe and generated parameters for use in future modelling analyses. METHODS A population-based cohort was recruited from a household census in 12 communities. A baseline survey was carried out in 1998-2000 with follow-up surveys after 3 and 5 years. Statistical distributions were fitted to reported within-partnership numbers of total, unprotected and protected sex acts in the past two weeks. Multilevel linear and logistic regression models were constructed to assess predictors of the frequency of unprotected sex and consistent condom use. RESULTS A normal distribution of ln(sex acts+1) provided the best fit for total and unprotected sex acts for men and women. A negative binomial distribution applied to the untransformed data provided the best fit for protected sex acts. Condom use within partnerships was predominantly bimodal with at least 88% reporting zero or 100% use. Both men and women reported fewer unprotected sex acts with non-regular compared to regular partners (men: 0.26 fewer every two weeks (95% confidence interval 0.18-0.34); women: 0.16 (0.07-0.23)). Never and previously married individuals reported fewer unprotected sex acts than currently married individuals (never married men: 0.64 (0.60-0.67); previously married men: 0.59 (0.50-0.67); never married women: 0.51 (0.45-0.57); previously married women: 0.42 (0.37-0.47)). These variables were also associated with more consistent condom use. DISCUSSION We generated parameters that will be useful for defining transmission models of HIV and other STIs, which rely on a valid representation of the underlying sexual network that determines spread of an infection. This will enable a better understanding of the spread of HIV and other STDs in this rural sub-Saharan population.
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Affiliation(s)
- Jennifer Smith
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Constance Nyamukapa
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Simon Gregson
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - James Lewis
- MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Christina Schumacher
- Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, United States of America
| | - Phyllis Mushati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Tim Hallett
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Geoff Garnett
- Global Development, Bill and Melinda Gates Foundation, Seattle, Washington, United States of America
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Analytic review of modeling studies of ARV Based PrEP interventions reveals strong influence of drug-resistance assumptions on the population-level effectiveness. PLoS One 2013; 8:e80927. [PMID: 24282559 PMCID: PMC3840039 DOI: 10.1371/journal.pone.0080927] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Accepted: 10/08/2013] [Indexed: 11/29/2022] Open
Abstract
Background Four clinical trials have shown that oral and topical pre-exposure prophylaxis (PrEP) based on tenofovir may be effective in preventing HIV transmission. The expected reduction in HIV transmission and the projected prevalence of drug resistance due to PrEP use vary significantly across modeling studies as a result of the broad spectrum of assumptions employed. Our goal is to quantify the influence of drug resistance assumptions on the predicted population-level impact of PrEP. Methods All modeling studies which evaluate the impact of oral or topical PrEP are reviewed and key assumptions regarding mechanisms of generation and spread of drug-resistant HIV are identified. A dynamic model of the HIV epidemic is developed to assess and compare the impact of oral PrEP using resistance assumptions extracted from published studies. The benefits and risks associated with ten years of PrEP use are evaluated under identical epidemic, behavioral and intervention conditions in terms of cumulative fractions of new HIV infections prevented, resistance prevalence among those infected with HIV, and fractions of infections in which resistance is transmitted. Results Published models demonstrate enormous variability in resistance-generating assumptions and uncertainty in parameter values. Depending on which resistance parameterization is used, a resistance prevalence between 2% and 44% may be expected if 50% efficacious oral PrEP is used consistently by 50% of the population over ten years. We estimated that resistance may be responsible for up to a 10% reduction or up to a 30% contribution to the fraction of prevented infections predicted in different studies. Conclusions Resistance assumptions used in published studies have a strong influence on the projected impact of PrEP. Modelers and virologists should collaborate toward clarifying the set of resistance assumptions biologically relevant to the PrEP products which are already in use or soon to be added to the arsenal against HIV.
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Okano JT, Blower S. HIV treatment, preexposure prophylaxis, and drug resistance: reconciling conflicting predictions from mathematical models. J Infect Dis 2013; 209:163-4. [PMID: 24133183 DOI: 10.1093/infdis/jit544] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Justin T Okano
- Center for Biomedical Modeling, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles
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Mimiaga MJ, White JM, Krakower DS, Biello KB, Mayer KH. Suboptimal awareness and comprehension of published preexposure prophylaxis efficacy results among physicians in Massachusetts. AIDS Care 2013; 26:684-93. [PMID: 24116985 DOI: 10.1080/09540121.2013.845289] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In 2010, the centre for the AIDS Programme of Research in South Africa (CAPRISA)004 and iPrEx trials (microbicide gel containing tenofovir and oral pill containing tenofovir-emtricitabine, respectively) demonstrated that antiretroviral preexposure prophylaxis (PrEP) reduced the risk of HIV acquisition among high-risk individuals. To determine the facilitators and barriers to PrEP provision by health-care providers, we conducted an online, quantitative survey of Massachusetts-area physicians following the publication of the CAPRISA and iPrEx results. We assessed awareness and comprehension of efficacy data, prescribing experience, and anticipated provision of oral and topical PrEP among physicians, as well as demographic and behavioral factors associated with PrEP awareness and prescribing intentions. The majority of HIV specialists and generalist physicians were aware of data from these PrEP trials and able to correctly interpret the results, however, correct interpretation of findings tended to vary according to specialty (i.e., HIV specialists had greater awareness than generalists). In addition, provider concerns regarding PrEP efficacy and safety, as well its ability to divert funds from other HIV prevention resources, were associated with decreased intentions to prescribe both oral and topical PrEP. Findings suggest that a substantial proportion of physicians who may have contact with at-risk individuals may benefit from interventions that provide accurate data on the risks and benefits of PrEP in order to facilitate effective PrEP discussions with their patients. Future studies to develop and test interventions aimed at health-care providers should be prioritized to optimize implementation of PrEP in clinical settings.
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Affiliation(s)
- Matthew J Mimiaga
- a Department of Psychiatry , Harvard Medical School/Massachusetts General Hospital , Boston , MA , USA
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50
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Abstract
The impressive advances in antiretroviral (ARV) therapy of chronic human immunodeficiency virus (HIV) infections during the last decade and the availability of potent ARV drugs have fueled interest in using chemoprophylaxis as a novel HIV prevention strategy. Preexposure prophylaxis (PrEP) refers to the use of ARV drugs in HIV-negative persons to prevent HIV infection. The rationale for PrEP builds on the success of ARV prophylaxis in preventing mother-to-child transmission of HIV and on a large body of animal studies that show the efficacy of PrEP against mucosal and parenteral infection. We focus on oral administration of ARV drugs for prevention of HIV infection. Identifying an effective prophylactic pill that individuals can take outside the setting of sexual intercourse precludes the necessity to disclose such use to their partners, thereby empowering those who might not be in a position to negotiate with their partners. Several human clinical trials evaluating the efficacy of daily regimens of the HIV reverse-transcriptase (RT) inhibitors tenofovir disoproxil fumarate (TDF) or Truvada (TDF and emtricitabine [FTC]) are under way among high-risk populations. The results of one trial among men who have sex with men showed that daily Truvada was safe and effective, providing the first support for oral PrEP as a prevention strategy. Here we outline the preclinical and clinical research on oral PrEP, pharmacologic considerations, and future directions and challenges.
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Affiliation(s)
- Walid Heneine
- Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV, Hepatitis, STD, and Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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