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Abstract
Introduction:
This article presents recent developments in biomedical interventions for prevention of sexual transmission of the human immunodeficiency virus (HIV) infection.
Materials and methods:
A review of results from randomised clinical trials on the use of antiretroviral (ARV) medications and other biomedical methods to prevent the transmission and acquisition of HIV infection.
Results:
Pre-exposure prophylaxis (PrEP) refers to the provision of ARV medications to uninfected persons at high risk of HIV infection either in the form of topical agents, e.g. vaginal microbicide gels, or orally administered tablets. The Caprissa study demonstrated the efficacy of vaginal microbicides, the Vaginal and Oral Interventions to Control the Epidemic (VOICE) study however was not able to confirm these results. Oral PrEP was found to be efficacious in the iPrEx study on men who have sex with men (MSM), and among heterosexual couples in the Partners-PrEP and the TDF2 studies in Africa. The HPTN 052 trial demonstrated that the provision of early ARV treatment was able to prevent transmission of HIV by 92% compared with delayed treatment. This has led to enthusiasm to roll out treatment as prevention (TasP) programmes. Encouraging results from studies on male circumcision to prevent HIV acquisition have resulted in several implementation projects in Africa. Another encouraging result has been the success, albeit modest, of the prime-boost combination RV144 vaccine trial in Thailand.
Conclusion:
New advances in prevention strategies are urgently needed to slow down the HIV pandemic. Recent developments particularly in the form of PrEP and TasP have given new hope that we will be able to achieve this goal.
... TasP is most widely referred to as one strategy within a set of HIV prevention programs, often referred to as a continuum, cascade or combination prevention strategy [1,33,36,40,41]. In addition to TasP, other HIV intervention strategies within health care systems include voluntary medical male circumcision, campaigns to increase HIV testing rates, condom availability and (in some settings) pre-and post-exposure prophylaxis (i.e., PEP and PreP) [38,[40][41][42]. As a result, the successful and ethical implementation of TasP relies heavily on the capacity of health systems to accommodate its introduction. ...
... For example, effectiveness trials might demonstrate the potential for a skewing of beneficial impacts among various population sub-groups (e.g., differential uptake across social strata; variegations in the number and strength of barriers to access along the social gradient) [22,44]. Unintended effects on individual-level behavior were also discussed in the literature, particularly risk compensation behavior (e.g., "condom migration" effects) [24,42,45,46]. The potential for risk compensation has led some to ask how this effect could potentially undermine or blunt the preventative aspects of TasP, reinforcing arguments that point to the necessity of maintaining and perhaps enhancing current standards of HIV prevention (e.g., risk-reduction counseling in clinical settings) in TasP implementation and scale-up [46]. ...
... For these authors, TasP's capacity to be effective requires ongoing commitments to human rights, including the provision of access to non-discriminatory services, policies and laws [8]. In particular, laws that criminalize HIV transmission have been identified as a significant socio-structural barrier to the ethical and effective scaling up of TasP, as well as other HIV-related interventions in which TasP is implicated (e.g., routine HIV testing) [8,42]. ...
Background
Despite the evidence showing the promise of HIV treatment as prevention (TasP) in reducing HIV incidence, a variety of ethical questions surrounding the implementation and “scaling up” of TasP have been articulated by a variety of stakeholders including scientists, community activists and government officials. Given the high profile and potential promise of TasP in combatting the global HIV epidemic, an explicit and transparent research priority-setting process is critical to inform ongoing ethical discussions pertaining to TasP.
Methods
We drew on the Arksey and O’Malley framework for conducting scoping review studies as well as systematic approaches to identifying empirical and theoretical gaps within ethical discussions pertaining to population-level intervention implementation and scale up. We searched the health science database PubMed to identify relevant peer-reviewed articles on ethical and implementation issues pertaining to TasP. We included English language articles that were published after 2009 (i.e., after the emergence of causal evidence within this field) by using search terms related to TasP. Given the tendency for much of the criticism and support of TasP to occur outside the peer-reviewed literature, we also included grey literature in order to provide a more exhaustive representation of how the ethical discussions pertaining to TasP have and are currently taking place. To identify the grey literature, we systematically searched a set of search engines, databases, and related webpages for keywords pertaining to TasP.
Results
Three dominant themes emerged in our analysis with respect to the ethical questions pertaining to TasP implementation and scale-up: (a) balancing individual- and population-level interests; (b) power relations within clinical practice and competing resource demands within health care systems; (c) effectiveness considerations and socio-structural contexts of HIV treatment experiences within broader implementation contexts.
Conclusion
Ongoing research and normative deliberation is required in order to successfully and ethically scale-up TasP within the continuum of HIV care models. Based on the results of this scoping review, we identify several ethical and implementation dimensions that hold promise for informing the process of scaling up TasP and that could benefit from new research.
... 4,5,6 The arsenal of HIV prevention strategies has expanded, from conventional methods of HIV testing and counselling, promotion of condoms, blood screening, education and behaviour modification, harm reduction for injecting drug users, treatment of sexually-transmitted infections, to newer methods, for example medical male circumcision and the use of antiretroviral drugs for pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP). 7 Ending AIDS as a public health threat by 2030 is feasible if high HIV burden cities fast-track their AIDS responses that include these new approaches. Since the World AIDS Day 2014 launch, mayors and other municipal leaders have joined forces with civil society representatives to action the Paris Declaration on Fast-Track Cities. ...
... There currently is no way to reverse HIV infection, but it is treatable, manageable, and preventable (WHO, n.d.-b;Del Rio, 2014). In 2012, the U.S. Food and Drug Administration (FDA) approved a biomedical prevention method, the daily oral pill known as pre-exposure prophylaxis or PrEP (Chan, 2012;Huang, 2018). Results from clinical research trials indicate that PrEP is safe to be used in a diversity of populations, including heterosexual men and women (Thigpen et al., 2012;Baeten et al., 2012) MSM, (Grant et al., 2010). ...
Individuals who are at high risk of contracting HIV should have equitable access to preventive measures, such as pre-exposure prophylaxis (PrEP). We conducted a retrospective data extract from the electronic medical records of federally-qualified health centers in New York City from 2016 to 2018. Descriptive statistics are presented, stratified by those who have been prescribed PrEP and those who have not. We created a variable called "ever-female" which includes individuals assigned female at birth or who have ever identified as female. A chi-square test was performed to determine the statistical significance between variables as p < .05. A total of 9659 patients met inclusion criteria for the study. Patients who were prescribed PrEP were significantly associated with being white and never-female, with 38.2% of those prescribed PrEP identifying as white and 83.8% of those prescribed PrEP categorized as never-female. Patients of trans experience were 9.6% of the PrEP cohort and 1.5% of the never PrEP cohort (p < .001). Patients identifying as Black/African American made up 19.8% of patients prescribed PrEP and 49.8% of those never prescribed PrEP (p < .001). Patients with the lowest reported income composed 48.4% of those prescribed PrEP compared to 69.3% of patients who were never prescribed PrEP (p < .001). These findings indicate that key demographic categories may not be accessing PrEP as much as would be expected for their level of risk. Barriers to access of PrEP for women and other at-risk, under-represented populations should be further studied.
... provision of ARV once infected partners' immune systems were declining). This has encouraged the development of TasP programs [47]. However, all biomedical strategies depend on 1) patients' acceptance and adherence, and 2) healthcare providers' belief that these interventions are needed. ...
... The current study reveals how decisions to initiate TasP may be strongly influenced by both the ability to keep one's self healthy, as well as the ability to protect others from infection. Furthermore, the findings offer insight into the complex and sometimes controversial narratives that continue to emerge regarding risk compensation practices in the context of TasP [36,37]. This remains an area that requires more investigation to fully inform ethical approaches to implementing and scaling up TasP in ways that do not exacerbate 'victim blaming' [38]. ...
Background
Despite evidence supporting the preventative potential of HIV Treatment as Prevention (TasP), scientific experts and community stakeholders have suggested that the success of TasP at the population level will require overcoming a set of complex and population-specific implementation challenges. For example, the factors that might influence decisions to initiate ‘early’ treatment have yet to be thoroughly understood; neither have questions about the factors that enhance or impede their ability to achieve long-term adherence to ARVs or the social norms regarding various treatment regimens been examined in detail. This knowledge gap may hamper opportunities to effectively develop public health practices that are informed by the various challenges and opportunities related to TasP implementation and scale up.
Methods
Drawing on 50 in-depth, individual interviews with young men ages 18–24 in Vancouver, Canada, this study examines young men’s perspectives regarding factors that might affect their engagement with TasP.
Results
While findings from the current study indicate young men generally have a high receptiveness to TasP, our findings also identify key social and structural forces that will warrant ongoing consideration for TasP implementation. For example, participants described how an enhanced awareness regarding treatment (including awareness of the universal availability of treatment in Vancouver) would be a necessary, but not sufficient, condition to decide to endorse TasP. Their decisions about engaging in HIV care in the context of TasP (e.g., HIV testing, treatment initiation, long-term adherence) also appear to be contingent on their ability to negotiate or ‘balance’ the risks and benefits to themselves and others. The findings also offer insight into the complex and sometimes controversial narratives that continue to emerge regarding risk compensation practices in the context of TasP.
Conclusion
Based on the results of this study, we identify several areas that hold promise for informing the effective scale up of TasP, including new information regarding implementation adaptation strategies.
... Le plus étudié est un gel de ténofovir qui a été décrit dans l'étude CAPRISA 004 comme non toxique et efficace pour réduire le risque d'infection à VIH chez les femmes qui l'ont utilisé avant et après un rapport sexuel vaginal (Abdool Karim et al., 2010). Cependant, des résultats contraires ont été obtenus dans l'étude VOICE (Vaginal and Oral Interventions to Control the Epidemic) (Chan, 2012). Ce gel est actuellement évalué dans l'étude FACTS 001, un essai de phase III testant le même schéma que l'étude CAPRISA 004 (résultats prévus en 2014). ...
Antigen-presenting cells (APCs) present at mucosal sites are among the first HIV-1 target cells and contribute to the spread of infection. During my thesis, I studied HIV transfer from macrophages (Mφ) and dendritic cells (DCs) to CD4-T lymphocytes. I showed that APCs were able to efficiently transfer HIV particles to lymphocytes, but through different mechanisms: Mφ rapidlytransferred HIV by direct trans-transfer, whereas DCs were mainly implicated in cistransfer (after production of de novo HIV). Moreover, I have demonstrated that these two modes of transfer were inhibited by neutralizing antibodies (NAb) in both type ofcocultures. Very interestingly, I showed that anti-gp120 NAb inhibit more efficiently HIV transfer in Mφ/T than in DCs/T cocultures and T cells infection by free viral particles. These findings highlight the major contributions of various mucosal target cells in HIV transfer and demonstrate the potent role of NAb on inhibition of cell-to-cell transfer.
Objectives:
Population mixing patterns can greatly inform allocation of HIV prevention interventions such as treatment as prevention (TasP) or preexposure prophyloaxis (PrEP). Characterizing contact patterns among subgroups can help identify the specific combinations of contact expected to result in the greatest number of new infections.
Setting:
Baseline data from an intervention to reduce HIV related risk behaviors in male PWID the northern Vietnamese province of Thai Nguyen was used for the analysis.
Methods:
Egocentric network data was provided by PWID who reported any drug injection equipment sharing in the previous 3 months. Age-dependent mixing was assessed to explore its epidemiological implications on risk of HIV transmission risk (among those HIV infected) and HIV acquisition risk (among those not infected) in PWID.
Results:
A total of 1,139 PWID collectively reported 2,070 equipment sharing partnerships in the previous 3 months. Mixing by age identified the 30-34 and 35-39 year age groups as the group from whom the largest number of new infections were transmitted, making them primary targets for TasP. Among the uninfected, 25-29, 30-35, and 35-39 year age groups had the highest HIV acquisition rate, making them the primary targets for PrEP.
Conclusions:
Collection and analysis of contact patterns in PWID is feasible and can greatly inform infectious disease dynamics and targeting of appropriate interventions. Results presented also provide much needed empirical data on mixing to improve mathematical models of diseases transmission in this population.
Introduction:
Successful HIV prevention and treatment requires evidence-based approaches that combine biomedical strategies with behavioral interventions that are socially and culturally appropriate for the population or community being prioritized. Although there has been a push for a combination approach, how best to integrate different strategies into existing behavioral HIV prevention interventions remains unclear. The need to develop effective combination approaches is of particular importance for men who have sex with men (MSM), who face a disproportionately high risk of HIV acquisition.
Materials and methods:
We collaborated with Latino male couples and providers to adapt Connect 'n Unite, an evidence-based intervention for Black male couples, for Latino male couples. We conducted a series of three focus groups, each with two cohorts of couples, and one focus group with providers. A purposive stratified sample of 20 couples (N = 40, divided into two cohorts) and 10 providers provided insights into how to adapt and integrate social, cultural, and biomedical approaches in a couples-based HIV/AIDS behavioral intervention.
Results:
The majority (N = 37) of the couple participants had no prior knowledge of the following new biomedical strategies: non-occupational post-exposure prophylaxis (nPEP); pre-exposure prophylaxis (PrEP); and HIV self-testing kits. After they were introduced to these biomedical interventions, all participants expressed a need for information and empowerment through knowledge and awareness of these interventions. In particular, participants suggested that we provide PrEP and HIV self-testing kits by the middle or end of the intervention. Providers suggested a need to address behavioral, social and structural issues, such as language barriers; and the promotion of client-centered approaches to increase access to, adaptation of, and adherence to biomedical strategies. Corroborating what couple participants suggested, providers agreed that biomedical strategies should be offered after providing information about these tools. Regarding culturally sensitive and responsive approaches, participants identified stigma and discrimination associated with HIV and sexual identity as barriers to care, language barriers and documentation status as further barriers to care, the couple-based approach as ideal to health promotion, and the need to include family topics in the intervention.
Discussion:
We successfully adapted an evidence-based behavioral HIV prevention intervention for Latino male couples. The adapted intervention, called Conectando Latinos en Pareja, integrates social, cultural, behavioral and biomedical strategies to address the HIV epidemic among Latino MSM. The study highlights the promise regarding the feasibility of implementing a combination approach to HIV prevention in this population.
Background Antiretroviral therapy that reduces viral replication could limit the transmission of human immunodeficiency virus type 1 (HIV-1) in serodiscordant couples. Methods In nine countries, we enrolled 1763 couples in which one partner was HIV-1-positive and the other was HIV-1-negative; 54% of the subjects were from Africa, and 50% of infected partners were men. HIV-1-infected subjects with CD4 counts between 350 and 550 cells per cubic millimeter were randomly assigned in a 1: 1 ratio to receive antiretroviral therapy either immediately (early therapy) or after a decline in the CD4 count or the onset of HIV-1-related symptoms (delayed therapy). The primary prevention end point was linked HIV-1 transmission in HIV-1-negative partners. The primary clinical end point was the earliest occurrence of pulmonary tuberculosis, severe bacterial infection, a World Health Organization stage 4 event, or death. Results As of February 21, 2011, a total of 39 HIV-1 transmissions were observed (incidence rate, 1.2 per 100 person-years; 95% confidence interval [CI], 0.9 to 1.7); of these, 28 were virologically linked to the infected partner (incidence rate, 0.9 per 100 person-years, 95% CI, 0.6 to 1.3). Of the 28 linked transmissions, only 1 occurred in the early-therapy group (hazard ratio, 0.04; 95% CI, 0.01 to 0.27; P<0.001). Subjects receiving early therapy had fewer treatment end points (hazard ratio, 0.59; 95% CI, 0.40 to 0.88; P = 0.01). Conclusions The early initiation of antiretroviral therapy reduced rates of sexual transmission of HIV-1 and clinical events, indicating both personal and public health benefits from such therapy.
Preexposure prophylaxis with antiretroviral agents has been shown to reduce the transmission of human immunodeficiency virus (HIV) among men who have sex with men; however, the efficacy among heterosexuals is uncertain.
We randomly assigned HIV-seronegative men and women to receive either tenofovir disoproxil fumarate and emtricitabine (TDF-FTC) or matching placebo once daily. Monthly study visits were scheduled, and participants received a comprehensive package of prevention services, including HIV testing, counseling on adherence to medication, management of sexually transmitted infections, monitoring for adverse events, and individualized counseling on risk reduction; bone mineral density testing was performed semiannually in a subgroup of participants.
A total of 1219 men and women underwent randomization (45.7% women) and were followed for 1563 person-years (median, 1.1 years; maximum, 3.7 years). Because of low retention and logistic limitations, we concluded the study early and followed enrolled participants through an orderly study closure rather than expanding enrollment. The TDF-FTC group had higher rates of nausea (18.5% vs. 7.1%, P<0.001), vomiting (11.3% vs. 7.1%, P=0.008), and dizziness (15.1% vs. 11.0%, P=0.03) than the placebo group, but the rates of serious adverse events were similar (P=0.90). Participants who received TDF-FTC, as compared with those who received placebo, had a significant decline in bone mineral density. K65R, M184V, and A62V resistance mutations developed in 1 participant in the TDF-FTC group who had had an unrecognized acute HIV infection at enrollment. In a modified intention-to-treat analysis that included the 33 participants who became infected during the study (9 in the TDF-FTC group and 24 in the placebo group; 1.2 and 3.1 infections per 100 person-years, respectively), the efficacy of TDF-FTC was 62.2% (95% confidence interval, 21.5 to 83.4; P=0.03).
Daily TDF-FTC prophylaxis prevented HIV infection in sexually active heterosexual adults. The long-term safety of daily TDF-FTC prophylaxis, including the effect on bone mineral density, remains unknown. (Funded by the Centers for Disease Control and Prevention and the National Institutes of Health; TDF2 ClinicalTrials.gov number, NCT00448669.).
Antiretroviral preexposure prophylaxis is a promising approach for preventing human immunodeficiency virus type 1 (HIV-1) infection in heterosexual populations.
We conducted a randomized trial of oral antiretroviral therapy for use as preexposure prophylaxis among HIV-1-serodiscordant heterosexual couples from Kenya and Uganda. The HIV-1-seronegative partner in each couple was randomly assigned to one of three study regimens--once-daily tenofovir (TDF), combination tenofovir-emtricitabine (TDF-FTC), or matching placebo--and followed monthly for up to 36 months. At enrollment, the HIV-1-seropositive partners were not eligible for antiretroviral therapy, according to national guidelines. All couples received standard HIV-1 treatment and prevention services.
We enrolled 4758 couples, of whom 4747 were followed: 1584 randomly assigned to TDF, 1579 to TDF-FTC, and 1584 to placebo. For 62% of the couples followed, the HIV-1-seronegative partner was male. Among HIV-1-seropositive participants, the median CD4 count was 495 cells per cubic millimeter (interquartile range, 375 to 662). A total of 82 HIV-1 infections occurred in seronegative participants during the study, 17 in the TDF group (incidence, 0.65 per 100 person-years), 13 in the TDF-FTC group (incidence, 0.50 per 100 person-years), and 52 in the placebo group (incidence, 1.99 per 100 person-years), indicating a relative reduction of 67% in the incidence of HIV-1 with TDF (95% confidence interval [CI], 44 to 81; P<0.001) and of 75% with TDF-FTC (95% CI, 55 to 87; P<0.001). Protective effects of TDF-FTC and TDF alone against HIV-1 were not significantly different (P=0.23), and both study medications significantly reduced the HIV-1 incidence among both men and women. The rate of serious adverse events was similar across the study groups. Eight participants receiving active treatment were found to have been infected with HIV-1 at baseline, and among these eight, antiretroviral resistance developed in two during the study.
Oral TDF and TDF-FTC both protect against HIV-1 infection in heterosexual men and women. (Funded by the Bill and Melinda Gates Foundation; Partners PrEP ClinicalTrials.gov number, NCT00557245.).
Background:
Various interventions have been adopted to reduce HIV transmission among sex workers and their clients but the effectiveness of these strategies has yet to be investigated using meta-analytic techniques.
Objectives:
To evaluate the effectiveness of behavioral interventions to reduce the transmission of HIV infection among sex workers and their clients in low- and middle-income countries.
Search methods:
The Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane HIV/AIDS group specialized register, the Cochrane Database of Systematic Reviews, MEDLINE, PsycINFO, Sociological Abstracts, CINAHL, Dissertation Abstract International (DAI), EMBASE, LILACS, BIOSIS, SciSearch, INDMED, Proquest, and various South Asian abstracting databases were included in the database list. The publication sites of the World Health Organization, the US Centers for Disease Control and Prevention, and other international research and non-governmental organizations also appeared in the database list.
Selection criteria:
Randomized controlled trials (RCTs) and quasi-RCTs examining the effects on HIV transmission risk of different behavioral interventions or comparing behavioral interventions with no intervention, where described any one of the outcome measures, such as HIV incidence and prevalence, STI incidence and prevalence, change in self-reported of condom use, and other HIV-related outcome.
Data collection and analysis:
Two authors independently assessed trials, extracted data and assessed the risk bias. Heterogeneity amongst trials was also tested.
Main results:
A total of 13 trials with 8,698 participants were included. Primary outcomes (HIV and STI prevalence and incidence) were reported in seven trials. Of these, HIV incidence was reported in only three trials. After a 6-month follow-up assessment, there was no evidence that social cognitive behavioral intervention was effective in reducing HIV incidence (RR 0.12, 95% CI 0.01 to 2.22). However, there was a reduction in HIV incidence at 3-month follow-up assessment of promotion of female and male condom (RR 0.07, 95% CI 0.00 to 1.38). Social cognitive interventions and promotion of female and male condom use were significantly reduced STIs incidence (RR 0.57, 95% CI 0.34 to 0.96) and (RR 0.63, 95% CI 0.45 to 0.88), respectively. Secondary outcomes were identified in 13 trials. Meta-analyses showed evidence that interventions to promote the use of female and male condoms do reduce non-condom use (RR 0.83, 95% CI 0.65 to 1.05) compared to promotion of male condoms alone, and that social cognitive interventions reduced drug use among sex workers (RR 0.65, 95% CI 0.36 to 1.16) compared to standard care.
Authors' conclusions:
Available evidence nevertheless suggests that compared with standard care or no intervention, behavioral interventions are effective in reducing HIV and the incidence of STIs amongst female sex workers (FSWs). Given the benefits of social cognitive theory and the promotion of condom use in reducing HIV/STI and the public health need to control transmission amongst FSWs, there is a clear finding in favour of behavioral interventions. However, it should be recognized that there is a lack of information about most other outcomes and target populations, and that all of the trials were conducted in low- and middle-income countries.
Antiretroviral therapy that reduces viral replication could limit the transmission of human immunodeficiency virus type 1 (HIV-1) in serodiscordant couples.
In nine countries, we enrolled 1763 couples in which one partner was HIV-1-positive and the other was HIV-1-negative; 54% of the subjects were from Africa, and 50% of infected partners were men. HIV-1-infected subjects with CD4 counts between 350 and 550 cells per cubic millimeter were randomly assigned in a 1:1 ratio to receive antiretroviral therapy either immediately (early therapy) or after a decline in the CD4 count or the onset of HIV-1-related symptoms (delayed therapy). The primary prevention end point was linked HIV-1 transmission in HIV-1-negative partners. The primary clinical end point was the earliest occurrence of pulmonary tuberculosis, severe bacterial infection, a World Health Organization stage 4 event, or death.
As of February 21, 2011, a total of 39 HIV-1 transmissions were observed (incidence rate, 1.2 per 100 person-years; 95% confidence interval [CI], 0.9 to 1.7); of these, 28 were virologically linked to the infected partner (incidence rate, 0.9 per 100 person-years, 95% CI, 0.6 to 1.3). Of the 28 linked transmissions, only 1 occurred in the early-therapy group (hazard ratio, 0.04; 95% CI, 0.01 to 0.27; P<0.001). Subjects receiving early therapy had fewer treatment end points (hazard ratio, 0.59; 95% CI, 0.40 to 0.88; P=0.01).
The early initiation of antiretroviral therapy reduced rates of sexual transmission of HIV-1 and clinical events, indicating both personal and public health benefits from such therapy. (Funded by the National Institute of Allergy and Infectious Diseases and others; HPTN 052 ClinicalTrials.gov number, NCT00074581.).
The epidemiological data reported from these countries paint a worrying picture of HIV infection and transmission among MSM. Common areas of concern include use of recreational drugs in combination with sex, use of the internet for sexual liaisons, growth of sex-on-premises venues, regional sex travel, and group sex parties. The symposium identified subpopulations of MSM who are at greater risk of HIV infections, in particular, young MSM. A recent review by van Griensven and van Wijngaarden on epidemiology and HIV prevention responses among MSM in Asia16 has called for rapid scale up of intervention programs in order to avert a public health catastrophe. The responses to the HIV epidemic among MSM in these countries vary and are determined by the capacity of community-based organisations, commitment and support from the government, as well as the legal and socio-cultural environments. A common feature is that HIV prevention programs for MSM have been difficult and under-resourced and therefore reach only a small proportion of MSM. Sex between men is criminalised in 19 out of 48 countries in the Asia Pacific region25 and is stigmatised by traditional Asian values and cultures. Many MSM are afraid to acknowledge their sexual orientation, to disclose it to their family and friends, and to access available health services such as HIV testing. In many of these countries, budgets for MSM-specific services are disproportionately low. Some countries such as China and Malaysia have been resistant to include MSM as important component of HIV/AIDS planning. In order to increase the response from government, public health, and medical sectors, it is necessary to reduce stigma and discrimination at multiple levels.26 Decriminalisation of homosexuality and a human rights approach to prevention are recommended by experts27 and the international agencies28,29 as crucial to achieve these goals. It is implicit that programs provided forMSMhave to involve community-based organisations and infected persons in planning and delivery. As exemplified by the work in Hong Kong and Japan, HIV prevention programs must be tailored to the local cultures. The programs must appeal to and address the needs of MSM clients. HIV and STI testing and counselling, increased access to lubricants and condoms, and outreach at various social venues are the basic services that non-government organisations must provide. To some degree this is the case in some developed countries in Asia. With relatively more funding, non-government organisations in Hong Kong and Singapore have been able to scale up programs, and to provide more comprehensive services that address sexual health needs and psychosocial issues among MSM. The clear commitment of government in HIV responses is also crucial. As is the case in Thailand, Hong Kong and Singapore, governments provide financial and technical assistance and coordinate MSM research and programming activities. Government financial support is crucial to ensure the survival of the non-government organisations and community-based organisations such that they would not have to rely on funding from donors or international agencies. In Singapore and Hong Kong, coalitions of clinicians, researchers, public health officials, and community-based organisations collaborate and have increased coverage of prevention services, leading to the most significant impact in reducing risk behaviours and HIV infection among MSM in the region. This partnership approach has also been recommended.12-14,16,27-29 A central body, supported by government, that coordinates MSM research and programming activities is critical to ensure a concerted and sustainable effort to reduce HIV among MSM populations in the region. Other countries must put into place similar coordination structures, increase resources and energise their community networks and organisations if they are to contain the alarming explosion of HIV transmission in their MSM communities.
Antiretroviral chemoprophylaxis before exposure is a promising approach for the prevention of human immunodeficiency virus (HIV) acquisition.
We randomly assigned 2499 HIV-seronegative men or transgender women who have sex with men to receive a combination of two oral antiretroviral drugs, emtricitabine and tenofovir disoproxil fumarate (FTC-TDF), or placebo once daily. All subjects received HIV testing, risk-reduction counseling, condoms, and management of sexually transmitted infections.
The study subjects were followed for 3324 person-years (median, 1.2 years; maximum, 2.8 years). Of these subjects, 10 were found to have been infected with HIV at enrollment, and 100 became infected during follow-up (36 in the FTC-TDF group and 64 in the placebo group), indicating a 44% reduction in the incidence of HIV (95% confidence interval, 15 to 63; P=0.005). In the FTC-TDF group, the study drug was detected in 22 of 43 of seronegative subjects (51%) and in 3 of 34 HIV-infected subjects (9%) (P<0.001). Nausea was reported more frequently during the first 4 weeks in the FTC-TDF group than in the placebo group (P<0.001). The two groups had similar rates of serious adverse events (P=0.57).
Oral FTC-TDF provided protection against the acquisition of HIV infection among the subjects. Detectable blood levels strongly correlated with the prophylactic effect. (Funded by the National Institutes of Health and the Bill and Melinda Gates Foundation; ClinicalTrials.gov number, NCT00458393.).
Randomized controlled trials in sub-Saharan Africa have shown that adult male circumcision reduces the risk of HIV acquisition in men by about 60%. In this article, we review recent data on the association of male circumcision and HIV/sexually transmitted infection in men and women. This includes a summary of data showing some evidence of an effect of male circumcision against genital ulcer disease, HSV-2 infection, human papillomavirus and Trichomonas vaginalis, but not Chlamydia trachomatis or Neisseria gonorrhoea in men. Longitudinal studies among HIV discordant couples suggest that male circumcision may provide some direct long-term benefit to women, which may start after complete wound healing. Circumcision may also protect against HIV acquisition in men who have sex with men (MSM) and those who practice unprotected anal intercourse (either exclusively or predominantly), although these data are not consistent. To date, there is little evidence from the few studies available of either unsafe practices or reported increases in risky behaviour, or adverse changes in sexual satisfaction and function. As countries in southern and eastern Africa scale up services, operational research will likely be useful to iteratively improve programme delivery and impact while identifying the best methods of integrating safe male circumcision services into HIV prevention strategies and strengthening health systems.
The Centre for the AIDS Program of Research in South Africa (CAPRISA) 004 trial assessed the effectiveness and safety of a
1% vaginal gel formulation of tenofovir, a nucleotide reverse transcriptase inhibitor, for the prevention of HIV acquisition
in women. A double-blind, randomized controlled trial was conducted comparing tenofovir gel (n = 445 women) with placebo gel (n = 444 women) in sexually active, HIV-uninfected 18- to 40-year-old women in urban and rural KwaZulu-Natal, South Africa.
HIV serostatus, safety, sexual behavior, and gel and condom use were assessed at monthly follow-up visits for 30 months. HIV
incidence in the tenofovir gel arm was 5.6 per 100 women-years (person time of study observation) (38 out of 680.6 women-years)
compared with 9.1 per 100 women-years (60 out of 660.7 women-years) in the placebo gel arm (incidence rate ratio = 0.61; P = 0.017). In high adherers (gel adherence > 80%), HIV incidence was 54% lower (P = 0.025) in the tenofovir gel arm. In intermediate adherers (gel adherence 50 to 80%) and low adherers (gel adherence < 50%),
the HIV incidence reduction was 38 and 28%, respectively. Tenofovir gel reduced HIV acquisition by an estimated 39% overall,
and by 54% in women with high gel adherence. No increase in the overall adverse event rates was observed. There were no changes
in viral load and no tenofovir resistance in HIV seroconverters. Tenofovir gel could potentially fill an important HIV prevention
gap, especially for women unable to successfully negotiate mutual monogamy or condom use.
At the individual level, higher HIV viral load predicts sexual transmission risk. We evaluated San Francisco's community viral load (CVL) as a population level marker of HIV transmission risk. We hypothesized that the decrease in CVL in San Francisco from 2004-2008, corresponding with increased rates of HIV testing, antiretroviral therapy (ART) coverage and effectiveness, and population-level virologic suppression, would be associated with a reduction in new HIV infections.
We used San Francisco's HIV/AIDS surveillance system to examine the trends in CVL. Mean CVL was calculated as the mean of the most recent viral load of all reported HIV-positive individuals in a particular community. Total CVL was defined as the sum of the most recent viral loads of all HIV-positive individuals in a particular community. We used Poisson models with robust standard errors to assess the relationships between the mean and total CVL and the primary outcome: annual numbers of newly diagnosed HIV cases. Both mean and total CVL decreased from 2004-2008 and were accompanied by decreases in new HIV diagnoses from 798 (2004) to 434 (2008). The mean (p = 0.003) and total CVL (p = 0.002) were significantly associated with new HIV cases from 2004-2008.
Reductions in CVL are associated with decreased HIV infections. Results suggest that wide-scale ART could reduce HIV transmission at the population level. Because CVL is temporally upstream of new HIV infections, jurisdictions should consider adding CVL to routine HIV surveillance to track the epidemic, allocate resources, and to evaluate the effectiveness of HIV prevention and treatment efforts.
The development of a safe and effective vaccine against the human immunodeficiency virus type 1 (HIV-1) is critical to pandemic control.
In a community-based, randomized, multicenter, double-blind, placebo-controlled efficacy trial, we evaluated four priming injections of a recombinant canarypox vector vaccine (ALVAC-HIV [vCP1521]) plus two booster injections of a recombinant glycoprotein 120 subunit vaccine (AIDSVAX B/E). The vaccine and placebo injections were administered to 16,402 healthy men and women between the ages of 18 and 30 years in Rayong and Chon Buri provinces in Thailand. The volunteers, primarily at heterosexual risk for HIV infection, were monitored for the coprimary end points: HIV-1 infection and early HIV-1 viremia, at the end of the 6-month vaccination series and every 6 months thereafter for 3 years.
In the intention-to-treat analysis involving 16,402 subjects, there was a trend toward the prevention of HIV-1 infection among the vaccine recipients, with a vaccine efficacy of 26.4% (95% confidence interval [CI], -4.0 to 47.9; P=0.08). In the per-protocol analysis involving 12,542 subjects, the vaccine efficacy was 26.2% (95% CI, -13.3 to 51.9; P=0.16). In the modified intention-to-treat analysis involving 16,395 subjects (with the exclusion of 7 subjects who were found to have had HIV-1 infection at baseline), the vaccine efficacy was 31.2% (95% CI, 1.1 to 52.1; P=0.04). Vaccination did not affect the degree of viremia or the CD4+ T-cell count in subjects in whom HIV-1 infection was subsequently diagnosed.
This ALVAC-HIV and AIDSVAX B/E vaccine regimen may reduce the risk of HIV infection in a community-based population with largely heterosexual risk. Vaccination did not affect the viral load or CD4+ count in subjects with HIV infection. Although the results show only a modest benefit, they offer insight for future research. (ClinicalTrials.gov number, NCT00223080.)
Roughly 3 million people worldwide were receiving antiretroviral therapy (ART) at the end of 2007, but an estimated 6.7 million were still in need of treatment and a further 2.7 million became infected with HIV in 2007. Prevention efforts might reduce HIV incidence but are unlikely to eliminate this disease. We investigated a theoretical strategy of universal voluntary HIV testing and immediate treatment with ART, and examined the conditions under which the HIV epidemic could be driven towards elimination.
We used mathematical models to explore the effect on the case reproduction number (stochastic model) and long-term dynamics of the HIV epidemic (deterministic transmission model) of testing all people in our test-case community (aged 15 years and older) for HIV every year and starting people on ART immediately after they are diagnosed HIV positive. We used data from South Africa as the test case for a generalised epidemic, and assumed that all HIV transmission was heterosexual.
The studied strategy could greatly accelerate the transition from the present endemic phase, in which most adults living with HIV are not receiving ART, to an elimination phase, in which most are on ART, within 5 years. It could reduce HIV incidence and mortality to less than one case per 1000 people per year by 2016, or within 10 years of full implementation of the strategy, and reduce the prevalence of HIV to less than 1% within 50 years. We estimate that in 2032, the yearly cost of the present strategy and the theoretical strategy would both be US$1.7 billion; however, after this time, the cost of the present strategy would continue to increase whereas that of the theoretical strategy would decrease.
Universal voluntary HIV testing and immediate ART, combined with present prevention approaches, could have a major effect on severe generalised HIV/AIDS epidemics. This approach merits further mathematical modelling, research, and broad consultation.
Maternal-infant transmission is the primary means by which young children become infected with human immunodeficiency virus type 1 (HIV). We conducted a randomized, double-blind, placebo-controlled trial of the efficacy and safety of zidovudine in reducing the risk of maternal-infant HIV transmission. HIV-infected pregnant women (14 to 34 weeks' gestation) with CD4+ T-lymphocyte counts above 200 cells per cubic millimeter who had not received antiretroviral therapy during the current pregnancy were enrolled. The zidovudine regimen included antepartum zidovudine (100 mg orally five times daily), intrapartum zidovudine (2 mg per kilogram of body weight given intravenously over one hour, then 1 mg per kilogram per hour until delivery), and zidovudine for the newborn (2 mg per kilogram orally every six hours for six weeks). Infants with at least one positive HIV culture of peripheral-blood mononuclear cells were classified as HIV-infected.
From April 1991 through December 20, 1993, the cutoff date for the first interim analysis of efficacy, 477 pregnant women were enrolled; during the study period, 409 gave birth to 415 live-born infants. HIV-infection status was known for 363 births (180 in the zidovudine group and 183 in the placebo group). Thirteen infants in the zidovudine group and 40 in the placebo group were HIV-infected. The proportions infected at 18 months, as estimated by the Kaplan-Meier method, were 8.3 percent (95 percent confidence interval, 3.9 to 12.8 percent) in the zidovudine group and 25.5 percent (95 percent confidence interval, 18.4 to 32.5 percent) in the placebo group. This corresponds to a 67.5 percent (95 percent confidence interval, 40.7 to 82.1 percent) relative reduction in the risk of HIV transmission (Z = 4.03, P = 0.00006). Minimal short-term toxic effects were observed. The level of hemoglobin at birth in the infants in the zidovudine group was significantly lower than that in the infants in the placebo group. By 12 weeks of age, hemoglobin values in the two groups were similar.
In pregnant women with mildly symptomatic HIV disease and no prior treatment with antiretroviral drugs during the pregnancy, a regimen consisting of zidovudine given ante partum and intra partum to the mother and to the newborn for six weeks reduced the risk of maternal-infant HIV transmission by approximately two thirds.
We examined the influence of viral load in relation to other risk factors for the heterosexual transmission of human immunodeficiency virus type 1 (HIV-1). In a community-based study of 15,127 persons in a rural district of Uganda, we identified 415 couples in which one partner was HIV-1-positive and one was initially HIV-1-negative and followed them prospectively for up to 30 months. The incidence of HIV-1 infection per 100 person-years among the initially seronegative partners was examined in relation to behavioral and biologic variables.
The male partner was HIV-1-positive in 228 couples, and the female partner was HIV-1-positive in 187 couples. Ninety of the 415 initially HIV-1-negative partners seroconverted (incidence, 11.8 per 100 person-years). The rate of male-to-female transmission was not significantly different from the rate of female-to-male transmission (12.0 per 100 person-years vs. 11.6 per 100 person-years). The incidence of seroconversion was highest among the partners who were 15 to 19 years of age (15.3 per 100 person-years). The incidence was 16.7 per 100 person-years among 137 uncircumcised male partners, whereas there were no seroconversions among the 50 circumcised male partners (P<0.001). The mean serum HIV-1 RNA level was significantly higher among HIV-1-positive subjects whose partners seroconverted than among those whose partners did not seroconvert (90,254 copies per milliliter vs. 38,029 copies per milliliter, P=0.01). There were no instances of transmission among the 51 subjects with serum HIV-1 RNA levels of less than 1500 copies per milliliter; there was a significant dose-response relation of increased transmission with increasing viral load. In multivariate analyses of log-transformed HIV-1 RNA levels, each log increment in the viral load was associated with a rate ratio of 2.45 for seroconversion (95 percent confidence interval, 1.85 to 3.26).
The viral load is the chief predictor of the risk of heterosexual transmission of HIV-1, and transmission is rare among persons with levels of less than 1500 copies of HIV-1 RNA per milliliter.
Taiwan established a nationwide surveillance system for human immunodeficiency virus (HIV) infection in 1989 and adopted a policy to provide all HIV-infected citizens with free access to highly active antiretroviral therapy (HAART) beginning in April 1997. This provided an opportunity to determine the effect of the widespread use of HAART on the evolution of the HIV epidemic.
We analyzed national HIV surveillance data. The HIV transmission rate was estimated by use of an exponential model of HIV epidemic evolution, with statistical projection over the interval between infection and detection to fit the surveillance data.
By the end of 2002, the cumulative number of HIV-infected citizens in Taiwan had reached 4390 (0.019% of the total population). After free access to HAART was established, the estimated HIV transmission rate decreased by 53% (0.391 vs. 0.184 new cases/prevalent case-year [95% confidence interval, 31%-65%]). There was no statistically significant change in the incidence of syphilis, in the general population or among HIV-positive patients, during the same period.
Providing free HAART to all HIV-infected citizens was associated with a 53% decrease in the HIV transmission rate and contributed to the control of the HIV epidemic in Taiwan.
After performing a review of prospective cohort evaluations, a focussed assessment of the current knowledge base and methodology pertaining to condom effectiveness against sexually transmissible infections, including HIV, was also conducted. Key observations included the point that studies of condom effectiveness are inherently complex and the potential forms of study bias all generally favour the null hypothesis. Perhaps the most challenging obstacle to rigor in these studies lies in determining which events of condom-protected sex occurred before infection as opposed to after infection when, in fact, infection occurs. This problem leads to misclassification bias; however, other sources of misclassification bias are common. Greater attention to the selection of a recall period, improved precision of self-reported measures, and accounting for condom use errors and problems are critical steps that must occur to promote rigor in these studies. Despite multiple shortcomings, prospective studies of condom effectiveness provide a reasonably favourable evaluation. Subsequent studies, however, should be designed to greatly reduce the error variance that predisposes condom effectiveness studies to type 2 errors that mask the potential value of condoms.
Interventions to reduce unprotected sex include individual counseling, social and behavioral support (such as peer education, assertiveness and relationship support, discussing attitudes and beliefs, videos). Small group and community interventions include group counseling or workshops, interventions in community areas, training community leaders, and community-building empowerment activities. The review found that these behavioral interventions can lead to significant risk reduction in MSM. Continued research is needed to identify which behavioral strategies are most effective in reducing transmission, and which intervention components are most effective in influencing those behaviors. More research is also needed on the most effective strategies for non-white MSM in wealthy countries, as well as for MSM in developing countries.
To review the epidemiology of HIV infection and prevention responses among men who have sex with men (MSM) in Asia.
A review of the existing scientific literature and governmental and non-governmental reports regarding the epidemiology of HIV infection and prevention responses among MSM in Asia.
Data show that HIV infection is now widespread among MSM throughout Asia. With the exception of the Philippines and Timor Leste, all countries for which information is available show epidemics of HIV infection among MSM, particularly in urban areas. Double-digit HIV prevalence among MSM is found in cities in China, Taiwan, India, Myanmar and Thailand. Incidence data, although scarce, confirm the ongoing transmission of HIV among MSM. Reports of new HIV diagnoses in MSM have been increasing in recent years, particularly in the developed economies of East Asia. HIV prevention responses have started in most Asian countries, but while the exact coverage and investment of such responses remain unclear, coverage seems to be far from the 60-80% level needed to have an effect on the HIV epidemic. Both Government and donor investment in prevention programs for MSM remain inadequate, especially when compared with the contribution of male-to-male transmission to the overall burden of the HIV epidemic.
Enlarged HIV prevention coverage and increased financial investment are necessary to reduce the spread of HIV infection among MSM in Asia.
Background:
Results of cohort studies and mathematical models have suggested that increased coverage with highly active antiretroviral therapy (HAART) could reduce HIV transmission. We aimed to estimate the association between plasma HIV-1 viral load, HAART coverage, and number of new cases of HIV in the population of a Canadian province.
Methods:
We undertook a population-based study of HAART coverage and HIV transmission in British Columbia, Canada. Data for number of HIV tests done and new HIV diagnoses were obtained from the British Columbia Centre for Disease Control. Data for viral load, CD4 cell count, and HAART use were extracted from the British Columbia Centre for Excellence in HIV/AIDS population-based registries. We modelled trends of new HIV-positive tests and number of individuals on HAART using generalised additive models. Poisson log-linear regression models were used to estimate the association between new HIV diagnoses and viral load, year, and number of individuals on HAART.
Findings:
Between 1996 and 2009, the number of individuals actively receiving HAART increased from 837 to 5413 (547% increase; p=0.002), and the number of new HIV diagnoses fell from 702 to 338 per year (52% decrease; p=0.001). The overall correlation between number of individuals on HAART and number of individuals newly testing positive for HIV per year was -0.89 (p<0.0001). For every 100 additional individuals on HAART, the number of new HIV cases decreased by a factor of 0.97 (95% CI 0.96-0.98), and per 1 log(10) decrease in viral load, the number of new HIV cases decreased by a factor of 0.86 (0.75-0.98).
Interpretation:
We have shown a strong population-level association between increasing HAART coverage, decreased viral load, and decreased number of new HIV diagnoses per year. Our results support the proposed secondary benefit of HAART used within existing medical guidelines to reduce HIV transmission.
Funding:
Ministry of Health Services and Ministry of Healthy Living and Sport, Province of British Columbia; US National Institute on Drug Abuse; US National Institutes of Health; Canadian Institutes of Health Research.
To synthesize the evidence on the risk of HIV transmission through unprotected sexual intercourse according to viral load and treatment with combination antiretroviral therapy (ART).
Systematic review and meta-analysis.
We searched Medline, Embase and conference abstracts from 1996-2009. We included longitudinal studies of serodiscordant couples reporting on HIV transmission according to plasma viral load or use of ART and used random-effects Poisson regression models to obtain summary transmission rates [with 95% confidence intervals, (CI)]. If there were no transmission events we estimated an upper 97.5% confidence limit.
We identified 11 cohorts reporting on 5021 heterosexual couples and 461 HIV-transmission events. The rate of transmission overall from ART-treated patients was 0.46 (95% CI 0.19-1.09) per 100 person-years, based on five events. The transmission rate from a seropositive partner with viral load below 400 copies/ml on ART, based on two studies, was zero with an upper 97.5% confidence limit of 1.27 per 100 person-years, and 0.16 (95% CI 0.02-1.13) per 100 person-years if not on ART, based on five studies and one event. There were insufficient data to calculate rates according to the presence or absence of sexually transmitted infections, condom use, or vaginal or anal intercourse.
Studies of heterosexual discordant couples observed no transmission in patients treated with ART and with viral load below 400 copies/ml, but data were compatible with one transmission per 79 person-years. Further studies are needed to better define the risk of HIV transmission from patients on ART.
The aim of this article is to outline key challenges facing the conduct of efficacy trials for biomedical strategies to prevent HIV infection.
The past 2-3 years have seen tumultuous development in this field. There have been disappointing findings in efficacy trials of vaginal microbicides, vaccines, the diaphragm and suppressive therapy for herpes, but a major breakthrough with the evidence that male circumcision prevents acquisition of infection. Meanwhile, clarity has started to emerge on a number of issues regarding trial conduct, including provision of standard of care, involvement of communities, and preparation for implementing effective interventions.
HIV prevention practice must continue to rely on condom promotion and other established strategies while biomedical approaches continue to be assessed and their implementation strategies evolve.
To review the evidence on the clinical effectiveness and cost-effectiveness of non-occupational postexposure prophylaxis (PEP) for HIV.
Eleven electronic databases were searched from inception to December 2007.
Selected studies were assessed, subjected to data extraction using a standard template and quality assessment using published criteria. Studies were synthesised using a narrative approach with full tabulation of results from all included studies.
One clinical effectiveness study meeting the inclusion criteria was identified, a cohort study of PEP in a high-risk HIV-negative homosexual male cohort in Brazil. The quality of the study was generally weak. Seroincidence in the cohort as a whole (2.9 per 100 person-years) was very similar to that expected in this population (3.1 per 100 person-years, p > 0.97), despite the seroconversion to HIV being 1/68 in the PEP group and 10/132 in the group not receiving PEP. High-risk sexual activities declined over time for both PEP and non-PEP users. Four economic evaluations met the inclusion criteria of the review. The methodological quality of the studies was mixed. The studies are constrained by a lack of published data on the clinical effectiveness of PEP after non-occupational exposure, with effectiveness data derived from one study of occupational PEP. Their generalisability to the UK is not clear. Results suggest that PEP following non-occupational exposure to HIV was cost saving for men who have unprotected receptive anal intercourse with men, whether the source partner is known to be HIV positive or not; heterosexuals after unprotected receptive anal intercourse; and intravenous drug users sharing needles with a known HIV-positive person. PEP following non-occupational exposure to HIV was cost-effective for all male-male intercourse (unprotected receptive and insertive anal intercourse, unprotected receptive oral sex, and 'other') and was possibly cost-effective for intravenous drug users and high-risk women. Four additional studies were identified giving further information about adverse events associated with PEP after non-occupational exposure to HIV. The majority of participants experienced adverse events with the most common being nausea and fatigue. Rates were generally higher in participants receiving triple therapy than in participants receiving dual therapy. Completion of PEP therapy was variable, ranging from 24% to 78% of participants depending on type of therapy. Toxicity was the main reason for discontinuation of treatment.
It is not possible to draw conclusions on the clinical effectiveness of non-occupational PEP for HIV because of the limited evidence available. The review of cost-effectiveness suggests that non-occupational PEP may be cost-effective, especially in certain population subgroups; however, the assumptions made and data sources used in the cost-effectiveness studies mean that their results should be used with caution.
The amount of protection that condoms provide for HIV and other sexually transmitted infections is unknown. Cohort studies of sexually active HIV serodiscordant couples with follow-up of the seronegative partner, provide a situation in which a seronegative partner has known exposure to the disease and disease incidence can be estimated. When some individuals use condoms and some do not, namely some individuals use condoms 100% of the time and some never use (0%) condoms, condom effectiveness can be estimated by comparing the two incidence rates. Condom effectiveness is the proportionate reduction in disease due to the use of condoms.
The objective of this review is to estimate condom effectiveness in reducing heterosexual transmission of HIV.
Studies were located using electronic databases (AIDSLINE, CINAHL, Embase, and MEDLINE) and handsearched reference lists.
For inclusion, studies had to have: (1) data concerning sexually active HIV serodiscordant heterosexual couples, (2) a longitudinal study design, (3) HIV status determined by serology, and (4) contain condom usage information on a cohort of always (100%) or never (0%) condom users.
Studies identified through the above search strategy that met the inclusion criteria were reviewed for inclusion in the analysis. Sample sizes, number of seroconversions, and the person-years of disease-free exposure time were recorded for each cohort. If available, the direction of transmission in the cohort (male-to-female, female-to-male), date of study enrollment, source of infection in the index case, and the presence of other STDs was recorded. Duplicate reports on the same cohort and studies with incomplete or nonsepecific information were excluded. HIV incidence was estimated from the cohorts of "always" users and for the cohorts of "never" users. Effectiveness was estimated from these two incidence estimates.
Of the 4709 references that were initially identified, 14 were included in the final analysis. There were 13 cohorts of "always" users that yielded an homogeneous HIV incidence estimate of 1.14 [95% C.I.:.56, 2.04] per 100 person-years. There were 10 cohorts of "never" users that appeared to be heterogeneous. The studies with the longest follow-up time, consisting mainly of studies of partners of hemophiliac and transfusion patients, yielded an HIV incidence estimate of 5.75 [95% C.I.: 3.16, 9.66] per 100 person-years. Overall effectiveness, the proportionate reduction in HIV seroconversion with condom use, is approximately 80%.
This review indicates that consistent use of condoms results in 80% reduction in HIV incidence. Consistent use is defined as using a condom for all acts of penetrative vaginal intercourse. Because the studies used in this review did not report on the "correctness" of use, namely whether condoms were used correctly and perfectly for each and every act of intercourse, effectiveness and not efficacy is estimated. Also, this estimate refers in general to the male condom and not specifically to the latex condom, since studies also tended not to specify the type of condom that was used. Thus, condom effectiveness is similar to, although lower than, that for contraception.
To evaluate the long-term impact of condom promotion programmes for vaginal and oral sex among female brothel-based sex workers in Singapore.
A pre-test/post-test comparison group followed by a time series design was used to compare trends in condom use for vaginal sex and cervical gonorrhoea incidence from 1990 to 2002 across cross-sectional samples of sex workers before and after programme implementation in 1995. The subsequent condom promotion programme for oral sex was evaluated using the interrupted time series with a retrospective pre-test to post-test matched control group design.
Sex workers completed a questionnaire before and 6 months after participation in educational sessions. Cervical and pharyngeal swabs were taken monthly for cultures for Neisseria gonorrhoeae.
Consistent condom use for vaginal sex increased significantly from < 45.0% before 1995 (pre-intervention period) to 95.1% in 2002, with a corresponding decline in cervical gonorrhoea incidence from > 30 to 2/1000 person-months. Adjustment for temporal changes in sociodemographic characteristics did not materially alter the trends. Consistent oral condom use increased significantly from < 50% before 1996 to 97.2% in 2002, with a corresponding decline in pharyngeal gonorrhoea from > 12 to 4.7/1000 person-months.
The interventions produced sustained high levels of condom use for vaginal and oral sex with corresponding declines in cervical and pharyngeal gonorrhoea incidence.
examine here the potential role of HAART in HIV prevention and the resulting eff ect this would have on the cost-eff ectiveness of the treatment. We also discuss a theoretical HAART-driven strategy to control the continued expansion of the HIV/AIDS pandemic.
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