HIV Incidence In South Africa Research Articles

The Effect of HIV Programs in South Africa on National HIV Incidence Trends, 2000-2019.

Recent studies have shown HIV incidence declines at a population level in several African countries. However, these studies have not directly quantified the extent to which incidence declines are attributable to different HIV programs. We calibrated a mathematical model of the South African HIV epidemic to age- and sex-specific data from antenatal surveys, household surveys, and death registration, using a Bayesian approach. The model was also parameterized using data on self-reported condom use, voluntary medical male circumcision (VMMC), HIV testing, and antiretroviral treatment (ART). Model estimates of HIV incidence were compared against the incidence rates that would have been expected had each program not been implemented. The model estimated incidence in 15-49 year olds of 0.84% (95% CI: 0.75% to 0.96%) at the start of 2019. This represents a 62% reduction (95% CI: 55% to 66%) relative to 2000, a 47% reduction (95% CI: 42% to 51%) relative to 2010, and a 73% reduction (95% CI: 68% to 77%) relative to the incidence that would have been expected in 2019 in the absence of any interventions. The reduction in incidence in 2019 because of interventions was greatest for ART and condom promotion, with VMMC and behavior change after HIV testing having relatively modest impacts. HIV program impacts differed significantly by age and sex, with condoms and VMMC having greatest impact in youth, and overall incidence reductions being greater in men than in women. HIV incidence in South Africa has declined substantially since 2000, with ART and condom promotion contributing most significantly to this decline.

Gender and Power Dynamics of Social Relationships Shape Willingness to Participate in Biomedical HIV Prevention Research Among South African Adolescents and Young Adults.

Background: Understanding young women and men's perceived barriers and facilitators to participation in biomedical HIV prevention research is important for designing youth friendly services (YFS) and acceptable technologies, which are necessary for preventing high sustained HIV incidence in South Africa. This study explores the multileveled barriers and facilitators to young men and women's willingness to participate in hypothetical biomedical HIV prevention research.Methods: Eight age- (16–18 and 19–24 years) and gender-stratified focus group discussions (FGDs) were conducted using semi-structured interview guides to explore young South African women and men's willingness, perceived barriers, and facilitators to participating in biomedical HIV prevention research. FGD transcripts were uploaded to NVivo and coded collaboratively with youth study team members. Thematic analysis using Bronfenbrenner's ecological model (individual, inter-personal, community, and societal) was used to guide a deductive coding procedure, which was documented and compared by gender.Results: Thirty-one participants from Durban and 34 from Soweto participated in FGDs. Individual facilitators for participation were discussed more by young men and included financial incentives and altruism. Concerns about side-effects of biomedical products were a common barrier. Interpersonal relationships with peers, intimate partners and caregivers influenced young people's willingness to participate in HIV prevention research, more so among young women. For young women, gendered power dynamics and distrust of intimate partners and parents influenced both communication regarding participation and willingness to participate in research that is often stigmatized, due to societal norms around women's sexuality. On a societal level, participants expressed distrust in medical and research institutions, however a sense of community that was developed with the study staff of this project, was a motivator to participate in future studies.Discussion: At each level of the ecological model, we found participants expressed gendered barriers and facilitators for participation. Gender norms as well as distrust of partners, parents, and health care professionals were key barriers that cut across all levels. At each level participants discussed facilitators that were youth-engaged, underscoring the need to implement YFS, establish trust and address gender inequities within future biomedical HIV prevention studies wishing to engage and retain South African youth.

The impact of the program for medical male circumcision on HIV in South Africa: analysis using three epidemiological models

Background: South Africa began offering medical male circumcision (MMC) in 2010. We evaluated the current and future impact of this program to see if it is effective in preventing new HIV infections. Methods: The Thembisa, Goals and Epidemiological Modeling Software (EMOD) HIV transmission models were calibrated to South Africa’s HIV epidemic, fitting to household survey data on HIV prevalence, risk behaviors, and proportions of men circumcised, and to programmatic data on intervention roll-out including program-reported MMCs over 2009-2017. We compared the actual program accomplishments through 2017 and program targets through 2021 with a counterfactual scenario of no MMC program. Results: The MMC program averted 71,000-83,000 new HIV infections from 2010 to 2017. The future benefit of the circumcision already conducted will grow to 496,000-518,000 infections (6-7% of all new infections) by 2030. If program targets are met by 2021 the benefits will increase to 723,000-760,000 infections averted by 2030. The cost would be $1,070-1,220 per infection averted relative to no MMC. The savings from averted treatment needs would become larger than the costs of the MMC program around 2034-2039. In the Thembisa model, when modelling South Africa’s 9 provinces individually, the 9-provinces-aggregate results were similar to those of the single national model. Across provinces, projected long-term impacts were largest in Free State, KwaZulu-Natal and Mpumalanga (23-27% reduction over 2017-2030), reflecting these provinces’ greater MMC scale-up. Conclusions: MMC has already had a modest impact on HIV incidence in South Africa and can substantially impact South Africa’s HIV epidemic in the coming years.

The impact of the program for medical male circumcision on HIV in South Africa: analysis using three epidemiological models.

Background: South Africa began offering medical male circumcision (MMC) in 2010. We evaluated the current and future impact of this program to see if it is effective in preventing new HIV infections. Methods: The Thembisa, Goals and Epidemiological Modeling Software (EMOD) HIV transmission models were calibrated to South Africa's HIV epidemic, fitting to household survey data on HIV prevalence, risk behaviors, and proportions of men circumcised, and to programmatic data on intervention roll-out including program-reported MMCs over 2009-2017. We compared the actual program accomplishments through 2017 and program targets through 2021 with a counterfactual scenario of no MMC program. Results: The MMC program averted 71,000-83,000 new HIV infections from 2010 to 2017. The future benefit of the circumcision already conducted will grow to 496,000-518,000 infections (6-7% of all new infections) by 2030. If program targets are met by 2021 the benefits will increase to 723,000-760,000 infections averted by 2030. The cost would be $1,070-1,220 per infection averted relative to no MMC. The savings from averted treatment needs would become larger than the costs of the MMC program around 2034-2039. In the Thembisa model, when modelling South Africa's 9 provinces individually, the 9-provinces-aggregate results were similar to those of the single national model. Across provinces, projected long-term impacts were largest in Free State, KwaZulu-Natal and Mpumalanga (23-27% reduction over 2017-2030), reflecting these provinces' greater MMC scale-up. Conclusions: MMC has already had a modest impact on HIV incidence in South Africa and can substantially impact South Africa's HIV epidemic in the coming years.

Challenges to HIV treatment adherence amongst adolescents in a low socio-economic setting in Cape Town.

BackgroundDespite the successful rollout of anti-retroviral therapy (ART) and steep declines in HIV incidence in South Africa, this has not been the case for adolescents (10–19 years). Adolescents on HIV treatment have lower rates of viral load suppression and adherence compared to adults and children.ObjectivesThis article reports on the adherence challenges faced by adolescents receiving ART in a primary health care clinic in a low socio-economic urban setting in Cape Town.MethodAn exploratory qualitative design was employed where data were collected through four focus group discussions with adolescents (n = 15) who received ART at a primary health care clinic in a low socio-economic urban setting in Cape Town and followed up with eight individual, semi-structured interviews with two adolescents from each focus group. Two key informant interviews were conducted with health workers at the clinic. Audio data were digitally recorded and transcribed verbatim. Data were analysed using content analysis.ResultsSchool commitments, strained teacher–learner relationships, negative household dynamics and ill treatment by non-biological caregivers were reported as major barriers to adherence. In addition, poor service delivery, missing or misplaced files and long waiting times came under major criticism. Fear of unintended disclosure of HIV status, stigma and discrimination, treatment fatigue and having unstructured lives negatively influenced adherence. Having a strong social support system and having life goals and ambitions were motivators to remain adherent.ConclusionThis study highlighted the complexity of ART adherence in the midst of juggling school, home life and personal life goals and aspirations. Interventions to improve adherence should address psychosocial factors such as treatment fatigue, disclosure and family and household dynamics, in addition to streamlining service delivery between the school and clinic.

The economic effects of lowering HIV incidence in South Africa: A CGE analysis

South Africa has the highest UNAIDS HIV severity rating: “generalised pandemic”. A country with this classification requires public health interventions aimed at the general population. This paper investigates the efficacy of one such policy, examining the national economic effects of an increase in condom use. We use an epidemiological model to estimate the impact of condom use on HIV infections distinguished by age, gender and race. The epidemiological model's outputs are input to an economy-wide dynamic general equilibrium model that distinguishes labour market participants by age, gender, race, labour market status and HIV status. We find that the programme generates gains in real consumption with a present value of approximately USD $30billion, or USD $2000 per household.

Use of HIV viral-load suppression to estimate the effect of community-wide home-based HIV counselling and testing and linkage to antiretroviral therapy on HIV incidence in South Africa: a mathematical modelling analysis

BackgroundHigh coverage of HIV counselling and testing (HCT) through community campaigns, which link most HIV-positive people to care, has the potential to decrease HIV incidence if most eligible people initiate antiretroviral therapy (ART) and are virally suppressed. The aim of our analysis was to use transmission models of HIV to estimate the effect of home-based HCT on HIV incidence in South Africa. MethodsWe did an observational cohort study of community-wide home-based HCT in KwaZulu-Natal, South Africa, from September, 2011 to May, 2013. Resident adults within a geographically defined community were offered HCT. HIV-positive people received point-of-care CD4 cell count results, counselling about HIV and ART, referral for HIV care, and follow-up visits at months 1, 3, 6, 9, and 12. We assessed risk behaviour and adherence for HIV-positive people on ART. HIV viral load was measured among all HIV-positive people at baseline, 6 months, and 12 months. Using baseline HCT data and estimates from the literature, we developed a compartmental, deterministic model of HIV incidence in KwaZulu-Natal, incorporating sexual behaviour and ART use. The model population was stratified by sex, age, sexual activity, circumcision status, and condom use. We assumed that viral suppression on ART decreases HIV transmission by 90%, ART dropout was 5% annually, and the transmission probability in acute HIV was 26-fold higher than in chronic infection. Model output for HIV prevalence and incidence was validated with independent HIV survey data. We modelled the effect of home-based HCT every 5 years on HIV incidence at 5, 10, and 20 years. FindingsOf 1296 adults, 1273 (98%) were tested for HIV, of whom 404 (32%) were positive. At baseline, 158 (39%) participants were on ART and 127 (32%) were eligible for ART according to national guidelines (CD4 count ≤350 cells per μL). The median CD4 cell count among ART-naive individuals was high (472 cells per μL). By month 6, 359 (88%) participants of the HIV-positive group identified at baseline had visited an HIV clinic, and by month 12, 111 had initiated ART. At month 12, HIV viral load was suppressed among 233 (58%) of all HIV-positive people and among 170 (71%) of HIV-positive people on ART (n=241). With use of the proportion of all HIV-positive participants with viral suppression to indicate ART coverage and adherence, modelling estimated that: HCT every 5 years with ART initiated at CD4 count of 350 cells per μL or less would decrease HIV incidence over 5, 10, and 20 years by 31·3%, 32·9%, and 33·1%, respectively; and ART initiation at the new WHO guideline level of CD4 count of 500 cells per μL or fewer would decrease incidence by 41·0%, 44·6%, and 45·3%, respectively. With each round of HCT (assuming ART initiation at CD4 count ≤350 cells per μL), the proportion of incident cases from acute infection increased from 26% to 31%, 37%, and 40% over 5, 10, and 20 years, respectively. InterpretationAchievable rates of HCT to ensure community-wide HIV testing and ART initiation at levels recommended by current South African guidelines could substantially decrease HIV incidence, if the majority of HIV-positive people achieve viral suppression. The effect will be limited by transmission from acutely infected, untreated individuals who are highly infectious. FundingWe acknowledge the support of the NIH Directors Award, RC4 AI092552.

HIV Treatment as Prevention: Systematic Comparison of Mathematical Models of the Potential Impact of Antiretroviral Therapy on HIV Incidence in South Africa

BackgroundMany mathematical models have investigated the impact of expanding access to antiretroviral therapy (ART) on new HIV infections. Comparing results and conclusions across models is challenging because models have addressed slightly different questions and have reported different outcome metrics. This study compares the predictions of several mathematical models simulating the same ART intervention programmes to determine the extent to which models agree about the epidemiological impact of expanded ART.Methods and FindingsTwelve independent mathematical models evaluated a set of standardised ART intervention scenarios in South Africa and reported a common set of outputs. Intervention scenarios systematically varied the CD4 count threshold for treatment eligibility, access to treatment, and programme retention. For a scenario in which 80% of HIV-infected individuals start treatment on average 1 y after their CD4 count drops below 350 cells/µl and 85% remain on treatment after 3 y, the models projected that HIV incidence would be 35% to 54% lower 8 y after the introduction of ART, compared to a counterfactual scenario in which there is no ART. More variation existed in the estimated long-term (38 y) reductions in incidence. The impact of optimistic interventions including immediate ART initiation varied widely across models, maintaining substantial uncertainty about the theoretical prospect for elimination of HIV from the population using ART alone over the next four decades. The number of person-years of ART per infection averted over 8 y ranged between 5.8 and 18.7. Considering the actual scale-up of ART in South Africa, seven models estimated that current HIV incidence is 17% to 32% lower than it would have been in the absence of ART. Differences between model assumptions about CD4 decline and HIV transmissibility over the course of infection explained only a modest amount of the variation in model results.ConclusionsMathematical models evaluating the impact of ART vary substantially in structure, complexity, and parameter choices, but all suggest that ART, at high levels of access and with high adherence, has the potential to substantially reduce new HIV infections. There was broad agreement regarding the short-term epidemiologic impact of ambitious treatment scale-up, but more variation in longer term projections and in the efficiency with which treatment can reduce new infections. Differences between model predictions could not be explained by differences in model structure or parameterization that were hypothesized to affect intervention impact. Please see later in the article for the Editors' Summary

O1-S06.04 Modelling the effectiveness of combination prevention from a house-to-house HIV testing platform in KwaZulu Natal, South Africa

BackgroundAvailable HIV prevention interventions are partially efficacious, but might offer the best strategy to control HIV through synergistic combination and targeting. Home-based HIV testing and counselling (HBCT), conducted house-to-house, provides...

Overestimation of the South African HIV incidence using the BED IgG assay

We thank Rehle et al. for their important study of HIV incidence in South Africa which we read with great interest. We agree with the authors that the incidence of HIV in South Africa is probably extremely high particularly among young women and believe that the study will help us focus HIV prevention efforts on appropriate subgroups. We have serious concerns however about the applicability of the BED IgG assay to the South African HIV epidemic. In light of recent evidence we are concerned that Rehle et al. have overstated the true absolute incidence of HIV in South Africa. As the name implies the BED assay was developed using sequences from HIV subtypes B D and E. To compensate for imperfect sensitivity and specificity Rehle et al. use a correction factor based on McDougal et al.s study of subtype B virus. Given that the majority of HIV infections considered by Rehle et al. were (apparently) of subtype C the applicability of the McDougal correction and indeed of the BED assay itself to these samples is problematic. More questions arise in light of a recent report by Karita et al. that the BED assay does not perform well in subtype C virus infections; investigators found a specificity of 71% (95% confidence interval (CI) 54 - 84%) substantially different from one estimate of specificity used in the McDougal correction (94% for infections more than 360 days in the past). In addition Karita et al. found that using the BED assay with the McDougal correction resulted in overestimation of incidence in prospective Ugandan samples (subtype not available but probably A and D) reporting a corrected BED incidence of 6.4% and a true incidence of 1.3 - 1.7%.4 We are therefore concerned that the incidence figures reported by Rehle et al. may be overestimates. If indeed these figures are incorrect this will make future comparisons with more accurate measures of incidence difficult and could lead to spurious conclusions with regard to the course of the epidemic. Given these concerns and the currentUNAIDS recommendation against using the BED assay for incidence estimation it would be helpful if the authors clarified their findings with a quantitative sensitivity analysis of their estimates. Until the BED assay has been further validated we believe that BED-derived estimates of HIV incidence must be interpreted with caution. (full-text)