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Can the Heterosexual HIV Epidemic be Eliminated in South Africa Using Combination Prevention? A Modeling Analysis.

ABSTRACT: Little is known about how combining efficacious interventions for human immunodeficiency virus (HIV) prevention could lead to HIV elimination. We used an agent-based simulation model, the HIV calibrated dynamic model, to assess the potential for HIV elimination in South Africa. We examined several scenarios (from continuation of the current status quo to perfect achievement of targets) with differing combinations of male condom use, adult male circumcision, HIV testing, and early antiretroviral therapy (ART). We varied numerous parameters, including the proportion of adult males circumcised, the frequency of condom use during sex acts, acceptance of HIV testing, linkage to health care, criteria for ART initiation, ART viral suppression rates, and loss to follow-up. Maintaining current levels of combination prevention would lead to increasing HIV incidence and prevalence in South Africa, while the perfect combination scenario was projected to eliminate HIV on a 50-year time scale from 2013 to 2063. Perfecting testing and treatment, without changing condom use or circumcision rates, resulted in an 89% reduction in HIV incidence but not elimination. Universal adult male circumcision alone resulted in a 21% incidence reduction within 20 years. Substantial decreases in HIV incidence are possible from sufficient uptake of both primary prevention and ART, but with continuation of the status quo, HIV elimination in South Africa is unlikely within a 50-year time scale.

SUBMITTER: Abuelezam NN

PROVIDER: S-EPMC4967594 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature

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Can the Heterosexual HIV Epidemic be Eliminated in South Africa Using Combination Prevention? A Modeling Analysis.

Abuelezam Nadia N NN McCormick Alethea W AW Fussell Thomas T Afriyie Abena N AN Wood Robin R DeGruttola Victor V Freedberg Kenneth A KA Lipsitch Marc M Seage George R GR

American journal of epidemiology 20160713 3

Little is known about how combining efficacious interventions for human immunodeficiency virus (HIV) prevention could lead to HIV elimination. We used an agent-based simulation model, the HIV calibrated dynamic model, to assess the potential for HIV elimination in South Africa. We examined several scenarios (from continuation of the current status quo to perfect achievement of targets) with differing combinations of male condom use, adult male circumcision, HIV testing, and early antiretroviral ...[more]

PMID: 27416841

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Project description:HIV prevention trials have demonstrated the effectiveness of a number of behavioral and biomedical interventions. HIV prevention packages are combinations of interventions and offer potential to significantly increase the effectiveness of any single intervention. Estimates of the effectiveness of prevention packages are important for guiding the development of prevention strategies and for characterizing effect sizes before embarking on large scale trials. Unfortunately, most research to date has focused on testing single interventions rather than HIV prevention packages. Here we report the results from agent-based modeling of the effectiveness of HIV prevention packages for men who have sex with men (MSM) in South Africa. We consider packages consisting of four components: antiretroviral therapy for HIV infected persons with CD4 count <350; PrEP for high risk uninfected persons; behavioral interventions to reduce rates of unprotected anal intercourse (UAI); and campaigns to increase HIV testing. We considered 163 HIV prevention packages corresponding to different intensity levels of the four components. We performed 2252 simulation runs of our agent-based model to evaluate those packages. We found that a four component package consisting of a 15% reduction in the rate of UAI, 50% PrEP coverage of high risk uninfected persons, 50% reduction in persons who never test for HIV, and 50% ART coverage over and above persons already receiving ART at baseline, could prevent 33.9% of infections over 5 years (95% confidence interval, 31.5, 36.3). The package components with the largest incremental prevention effects were UAI reduction and PrEP coverage. The impact of increased HIV testing was magnified in the presence of PrEP. We find that HIV prevention packages that include both behavioral and biomedical components can in combination prevent significant numbers of infections with levels of coverage, acceptance and adherence that are potentially achievable among MSM in South Africa.

Project description:BackgroundFor interventions to reach those they are intended for, an understanding of the factors that influence their participation, as well as the facilitators and barriers of participation are needed. This study explores factors associated with participation in a combination HIV prevention intervention targeting adolescent girls and young women (AGYW) aged 15-24-years-old, as well as the perspectives of AGYW, intervention implementers, and facilitators who participated in this intervention.MethodsThis study used mixed-methods approach with quantitative household survey data from 4399 AGYW aged 15-24-years-old in six of the ten districts in which the intervention was implemented. In addition, qualitative methods included a total of 100 semi-structured in-depth interviews and 21 focus group discussions in five of the ten intervention districts with 185 AGYW who participated in one or more of the key components of the intervention, and 13 intervention implementers and 13 facilitators. Thematic analysis was used to explore the perspectives of participating and implementing the intervention.ResultsFindings reveal that almost half of AGYW (48.4%) living in the districts where the intervention took place, participated in at least one of the components of the intervention. For both 15-19-year-olds and 20-24-year-olds, factors associated with increased participation in the intervention included being HIV negative, in school, never been pregnant, and having had a boyfriend. Experiencing intimate partner violence (IPV) and/or sexual violence in the past 12 months was associated with increased levels of participation in the intervention for 20-24-year-olds only. In our analysis of the qualitative data, facilitators to participation included motivating participants to join the interventions through explaining the benefits of the programme. Barriers included misguided expectations about financial rewards or job opportunities; competing responsibilities, interests or activities; family responsibilities including childcare; inappropriate incentives; inability to disrupt the school curriculum and difficulties with conducting interventions after school hours due to safety concerns; miscommunication about meetings; as well as struggles to reach out-of-school AGYW.ConclusionDesigners of combination HIV prevention interventions need to address the barriers to participation so that AGYW can attend without risking their safety and compromising their family, childcare and schooling responsibilities. Strategies to create demand need to include clear communication about the nature and potential benefits of such interventions, and the inclusion of valued incentives.

Project description:BackgroundStigma and discrimination ontinue to undermine the effectiveness of the HIV response. Despite a growing body of evidence of the negative relationship between stigma and HIV outcomes, there is a paucity of data available on the prevalence of stigma and its impact. We present a probabilistic cascade model to estimate the magnitude of impact stigma has on mother-to-child-transmission (MTCT).MethodsThe model was parameterized using 2010 data from Johannesburg, South Africa, from which loss-to-care at each stage of the antenatal cascade were available. Three scenarios were compared to assess the individual contributions of stigma, non-stigma related barriers, and drug ineffectiveness on the overall number of infant infections. Uncertainty analysis was used to estimate plausible ranges. The model follows the guidelines in place in 2010 when the data were extracted (WHO Option A), and compares this with model results had Option B+ been implemented at the time.ResultsThe model estimated under Option A, 35% of infant infections being attributed to stigma. This compares to 51% of total infections had Option B+ been implemented in 2010. Under Option B+, the model estimated fewer infections than Option A, due to the availability of more effective drugs. Only 8% (Option A) and 9% (Option B+) of infant infections were attributed to drug ineffectiveness, with the trade-off in the proportion of infections being between stigma and non-stigma-related barriers.ConclusionsThe model demonstrates that while the effect of stigma on retention of women at any given stage along the cascade can be relatively small, the cumulative effect can be large. Reducing stigma may be critical in reaching MTCT elimination targets, because as countries improve supply-side factors, the relative impact of stigma becomes greater. The cumulative nature of the PMTCT cascade results in stigma having a large effect, this feature may be harnessed for efficiency in investment by prioritizing interventions that can affect multiple stages of the cascade simultaneously.

Project description:INTRODUCTION:High levels of HIV seroconcordance at the population level reduce the potential for effective HIV transmission. However, the level of HIV seroconcordance is largely unknown among heterosexual couples in sub-Saharan Africa. We aimed to quantify the population level HIV seroconcordance in stable heterosexual couples in rural South Africa. METHODS:We followed adults (≥15 years old) using a population-based, longitudinal and open surveillance system in KwaZulu-Natal, South Africa, from 2003 to 2016. Sexual partnerships and HIV status were confirmed via household surveys and annual HIV surveillance. We calculated the proportions of HIV seroconcordance and serodiscordance in stable sexual partnerships and compared them to the expected proportions under the assumption of random mixing using individual-based microsimulation models. Among unpartnered individuals, we estimated the incidence rates and hazard of sexual partnership formation with HIV-positive or HIV-negative partners by participants' own time-varying HIV status. Competing risks survival regressions were fitted adjusting for sociodemographic and clinical factors. We also calculated Newman's assortativity coefficients. RESULTS:A total of 18,341 HIV-negative and 11,361 HIV-positive individuals contributed 154,469 person-years (PY) of follow-up. Overall, 28% of the participants were in stable sexual partnerships. Of the 677 newly formed stable sexual partnerships, 7.7% (95% CI: 5.8 to 10.0) were HIV-positive seroconcordant (i.e. both individuals in the partnership were HIV-positive), which was three times higher than the expected proportion (2.3%) in microsimulation models based on random mixing. The incidence rates of sexual partnership formation were 0.54/1000PY with HIV-positive, 1.12/1000PY with HIV-negative and 2.65/1000PY with unknown serostatus partners. HIV-positive individuals had 2.39 (95% CI: 1.43 to 3.99) times higher hazard of forming a sexual partnership with an HIV-positive partner than did HIV-negative individuals after adjusting for age, opposite-sex HIV prevalence (by 5-years age groups), HIV prevalence in the surrounding community, ART coverage and other sociodemographic factors. Similarly, forming a sexual partnership with an HIV-negative partner was 1.47 (95% CI: 1.01 to 2.14) times higher in HIV-negative individuals in the adjusted model. Newman's coefficient also showed that assortativity by participant and partner HIV status was moderate (r = 0.35). CONCLUSIONS:A high degree of population level HIV seroconcordance (both positive and negative) was observed at the time of forming new sexual partnerships. Understanding factors driving these patterns may help the development of strategies to bring the HIV epidemic under control.

Project description:Adolescents and young people account for 40% of all new HIV infections each year, with South Africa one of the hardest hit countries, and having the largest population of people living with HIV. Although adolescent HIV prevention has been delivered through diverse modalities in South Africa, and although family-based approaches for adolescent HIV prevention have great potential for highly affected settings such as South Africa, there is a scarcity of empirically tested family-based adolescent HIV preventive interventions in this setting. We therefore conducted focus groups and in-depth interviews with key informants including clinicians, researchers, and other individuals representing organizations providing HIV and related health services to adolescents and parents (N = 82). We explored family perspectives and interactions around topics such as communication about sex, HIV, and relationships. Participants described aspects of family interactions that presented both challenges and opportunities for family-based adolescent HIV prevention. Parent-child communication on sexual topics were taboo, with these conversations perceived by some adults as an invitation for children to engage in HIV risk behavior. Parents experienced social sanctions for discussing sex and adolescents who asked about sex were often viewed as disrespectful and needing discipline. However, participants also identified context-appropriate strategies for addressing family challenges around HIV prevention including family meetings, communal parenting, building efficacy around parent-adolescent communication around sexual topics, and the need to strengthen family bonding and positive parenting. Findings indicate the need for a family intervention and identify strategies for development of family-based interventions for adolescent HIV prevention. These findings will inform design of a family intervention to be tested in a randomized pilot trial (ClinicalTrials.gov #NCT02432352).

Project description:Building a successful combination prevention program requires understanding the community's local epidemiological profile, the social community norms that shape vulnerability to HIV and access to care, and the available community resources. We carried out a situational analysis in order to shape a comprehensive HIV prevention program that address local barriers to care at multiple contextual levels in the North West Province of South Africa.The situational analysis was conducted in two sub-districts in 2012 and guided by an adaptation of WHO's Strategic Approach, a predominantly qualitative method, including observation of service delivery points and in-depth interviews and focus groups with local leaders, providers, and community members, in order to recommend context-specific HIV prevention strategies. Analysis began during fieldwork with nightly discussions of findings and continued with coding original textual data from the fieldwork notebooks and a select number of recorded interviews.We conducted over 200 individual and group interviews and gleaned four principal social barriers to HIV prevention and care, including: HIV fatalism, traditional gender norms, HIV-related stigma, and challenges with communication around HIV, all of which fuel the HIV epidemic. At the different levels of response needed to stem the epidemic, we found evidence of national policies and programs that are mitigating the social risk factors but little community-based responses that address social risk factors to HIV.Understanding social and structural barriers to care helped shape our comprehensive HIV prevention program, which address the four 'themes' identified into each component of the program. Activities are underway to engage communities, offer community-based testing in high transmission areas, community stigma reduction, and a positive health, dignity and prevention program for stigma reduction and improve communication skills. The situational analysis process successfully shaped key programmatic decisions and cultivated a deeper collaboration with local stakeholders to support program implementation.

Project description:BACKGROUND:Young Southern African women have the highest HIV incidence globally. Pregnancy doubles the risk of HIV acquisition further, and maternal HIV acquisition contributes significantly to the paediatric HIV burden. Little data on combination HIV prevention interventions during pregnancy and lactation are available. We measured HIV incidence amongst pregnant and postpartum women receiving a community-based combination HIV prevention intervention in a high HIV incidence setting in South Africa. METHODS:A cohort study that included HIV-uninfected pregnant women was performed. Lay community-based workers provided individualized HIV prevention counselling and performed three-monthly home and clinic-based individual and couples HIV testing. Male partners were referred for circumcision, sexually transmitted infections or HIV treatment as appropriate. Kaplan-Meier analyses and Cox's regression were used to estimate HIV incidence and factors associated with HIV acquisition. RESULTS:The 1356 women included (median age 22.5 years) received 5289 HIV tests. Eleven new HIV infections were detected over 828.3 person-years (PY) of follow-up, with an HIV incidence rate of 1.33 infections/100 PY (95% CI: 0.74-2.40). Antenatally, the HIV incidence rate was 1.49 infections/100 PY (95% CI: 0.64-2.93) and postnatally the HIV incidence rate was 1.03 infections/100 PY (95% CI: 0.33-3.19). 53% of male partners received HIV testing and 66% of eligible partners received referral for circumcision. Women within known serodiscordant couples, and women with newly diagnosed HIV-infected partners, adjusted hazard ratio (aHR) = 32.7 (95% CI: 3.8-282.2) and aHR = 126.4 (95% CI: 33.8-472.2) had substantially increased HIV acquisition, respectively. Women with circumcised partners had a reduced risk of incident HIV infection, aHR = 0.22 (95% CI: 0.03-1.86). CONCLUSIONS:Maternal HIV incidence was substantially lower than previous regional studies. Community-based combination HIV prevention interventions may reduce high maternal HIV incidence in resource-poor settings. Expanded roll-out of home-based couples HIV testing and initiating pre-exposure prophylaxis for pregnant women within serodiscordant couples is needed in Southern Africa.

Dataset Information

Can the Heterosexual HIV Epidemic be Eliminated in South Africa Using Combination Prevention? A Modeling Analysis.

Publications

Can the Heterosexual HIV Epidemic be Eliminated in South Africa Using Combination Prevention? A Modeling Analysis.

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