HIV Incidence In Populations Research Articles

Comparison of Empirically Derived and Model-Based Estimates of Key Population HIV Incidence and the Distribution of New Infections by Population Group in Sub-Saharan Africa.

The distribution of new HIV infections among key populations, including female sex workers (FSWs), gay men and other men who have sex with men (MSM), and people who inject drugs (PWID) are essential information to guide an HIV response, but data are limited in sub-Saharan Africa (SSA). We analyzed empirically derived and mathematical model-based estimates of HIV incidence among key populations and compared with the Joint United Nations Programme on HIV/AIDS (UNAIDS) estimates. We estimated HIV incidence among FSW and MSM in SSA by combining meta-analyses of empirical key population HIV incidence relative to the total population incidence with key population size estimates (KPSE) and HIV prevalence. Dynamic HIV transmission model estimates of HIV incidence and percentage of new infections among key populations were extracted from 94 country applications of 9 mathematical models. We compared these with UNAIDS-reported distribution of new infections, implied key population HIV incidence and incidence-to-prevalence ratios. Across SSA, empirical FSW HIV incidence was 8.6-fold (95% confidence interval: 5.7 to 12.9) higher than total population female 15-39 year incidence, and MSM HIV incidence was 41.8-fold (95% confidence interval: 21.9 to 79.6) male 15-29 year incidence. Combined with KPSE, these implied 12% of new HIV infections in 2021 were among FSW and MSM (5% and 7% respectively). In sensitivity analysis varying KPSE proportions within 95% uncertainty range, the proportion of new infections among FSW and MSM was between 9% and 19%. Insufficient data were available to estimate PWID incidence rate ratios. Across 94 models, median proportion of new infections among FSW, MSM, and PWID was 6.4% (interquartile range 3.2%-11.7%), both much lower than the 25% reported by UNAIDS. Empirically derived and model-based estimates of HIV incidence confirm dramatically higher HIV risk among key populations in SSA. Estimated proportions of new infections among key populations in 2021 were sensitive to population size assumptions and were substantially lower than estimates reported by UNAIDS.

Inferring population HIV incidence trends from surveillance data of recent HIV infection among HIV testing clients.

Background:Measuring recent HIV infections from routine surveillance systems could allow timely and granular monitoring of HIV incidence patterns. We evaluated the relationship of two recent infection indicators with alternative denominators to true incidence patterns.Methods:We used a mathematical model of HIV testing behaviours, calibrated to population-based surveys and HIV testing services programme data, to estimate the number of recent infections diagnosed annually from 2010 to 2019 in Côte d’Ivoire, Malawi, and Mozambique. We compared two different denominators to interpret recency data: those at risk of HIV acquisition (HIV-negative tests and recent infections) and all people testing HIV positive. Sex and age-specific longitudinal trends in both interpretations were then compared with modelled trends in HIV incidence, testing efforts and HIV positivity among HIV testing services clients.Results:Over 2010–2019, the annual proportion of the eligible population tested increased in all countries, while positivity decreased. The proportion of recent infections among those at risk of HIV acquisition decreased, similar to declines in HIV incidence among adults (≥15 years old). Conversely, the proportion of recent infections among HIV-positive tests increased. The female-to-male ratio of the proportion testing recent among those at risk was closer to 1 than the true incidence sex ratio.Conclusion:The proportion of recent infections among those at risk of HIV acquisition is more indicative of HIV incidence than the proportion among HIV-positive tests. However, interpreting the observed patterns as surrogate measures for incidence patterns may still be confounded by different HIV testing rates between population groups or over time.

Implementation of Universal HIV Testing and Treatment to Reduce HIV Incidence in Botswana: the Ya Tsie Study.

Antiretroviral treatment (ART) can dramatically reduce the risk of HIV transmission, but the feasibility of scaling up HIV testing, linkage and treatment to very high population levels, and its impact on population HIV incidence, were unknown. We review key findings from a community-randomized trial in which we evaluated the impact of "universal test and treat" (UTT) on population HIV incidence in Botswana, a resource-constrained country with both high HIV prevalence and high ART coverage before study inception. We conducted a community-randomized trial (the "Ya Tsie" trial or Botswana Combination Prevention Project (BCPP)) in 30 villages in Botswana from 2013 to 2018, with the goal of determining whether a combination of prevention interventions-with a focus on universal HIV testing and treatment-would reduce population-level HIV incidence. The intervention included universal HIV testing (home-based and mobile), active linkage to HIV care and treatment with patient tracing for persons not linking, universal ART coverage, rapid ART start (at the first clinic visit), and enhanced male circumcision services. Botswana had very high HIV diagnosis, treatment, and viral suppression levels (approaching the UNAIDS "90-90-90" targets) prior to intervention roll-out. By study end, we were able to exceed the overall 95-95-95 coverage target of 86%: an estimated 88% of all persons living with HIV were on ART and had viral suppression in the Ya Tsie intervention arm. In addition, annual HIV incidence was 30% lower in the intervention arm as compared with the control arm over a 29-month follow-up period. With universal HIV testing and relatively simple linkage activities, it was possible to achieve one of the highest reported population levels of HIV diagnosis, linkage to care, and viral suppression globally and to reduce population HIV incidence by about one-third over a short period of time (< 3years). We were able to significantly increase population viral suppression and to decrease HIV incidence even in a resource-constrained setting with pre-existing very high testing and treatment coverage. Universal community-based HIV testing and tracing of individuals through the HIV care cascade were key intervention components.

Roll-out of first HIV pre-exposure prophylaxis services in the Democratic Republic of the Congo

Abstract Background In the Democratic Republic of the Congo (DR Congo), HIV prevalence is highest in key populations, specifically female sex workers and men who have sex with men, with estimates of 7% and 18%, respectively, compared with 1·2% in the general population. Pre-exposure prophylaxis (PrEP) is an evidence-based intervention to reduce HIV incidence in populations who are at substantial risk of acquiring HIV. Building the capacity of clinics and outreach programmes serving key populations is a critical first step in scaling-up PrEP services. Here, we describe a programme from the DR Congo's National AIDS Control Programme, US Centers for Disease Control and Prevention (CDC), and ICAP at Columbia University to initiate 350 clients from key population on PrEP in 2018. Methods With support from the National AIDS Control Programme and CDC, ICAP facilitated PrEP implementation at seven HIV care and treatment facilities in DR Congo. Capacity-building activities included: guidance on national planning; establishment of a national PrEP technical working group; and the development of PrEP training material for multidisciplinary facility teams to provide and monitor PrEP services. Training addressed: PrEP eligibility screening, initiation, and follow-up; PrEP retention and follow-up activities; and monitoring and evaluation of PrEP services. ICAP also provided ongoing on-site mentorship of clinic staff, and continuous evaluation of clinic procedures to ensure standardised PrEP service delivery across all facilities. Findings By February, 2018, 38 clinical staff and 48 peer outreach workers had completed a 6-day PrEP training course using ICAP's PrEP training curriculum; participant and facilitator manuals; job aids; and monitoring, evaluation, and reporting tools. Following the training, four sites in Kinshasa and three sites in Lubumbashi initiated PrEP services for the first time, resulting in successful achievement of the national PrEP targets. Interpretation Collaboration between national and global stakeholders resulted in the successful introduction of PrEP in DR Congo. PrEP implementation required extensive clinic training, tailoring of existing outreach activities to improve PrEP retention, inclusion of peer workers to help educate patients about PrEP, comprehensive monitoring and evaluation reporting, and ongoing mentoring of clinic staff. Lessons learned in DR Congo will be shared with other programmes in African countries that work with populations at risk of HIV. Project findings will also support the endorsement of national PrEP guidelines and the scale-up of PrEP in DR Congo. Funding US Centers for Disease Control and Prevention.

Universal test and treat and the HIV epidemic in rural South Africa: a phase 4, open-label, community cluster randomised trial

Universal antiretroviral therapy (ART), as per the 2015 WHO recommendations, might reduce population HIV incidence. We investigated the effect of universal test and treat on HIV acquisition at population level in a high prevalence rural region of South Africa. We did a phase 4, open-label, cluster randomised trial of 22 communities in rural KwaZulu-Natal, South Africa. We included individuals residing in the communities who were aged 16 years or older. The clusters were composed of aggregated local areas (neighbourhoods) that had been identified in a previous study in the Hlabisa subdistrict. The study statisticians randomly assigned clusters (1:1) with MapInfo Pro (version 11.0) to either the control or intervention communities, stratified on the basis of antenatal HIV prevalence. We offered residents repeated rapid HIV testing during home-based visits every 6 months for about 4 years in four clusters, 3 years in six clusters, and 2 years in 12 clusters (58 cluster-years) and referred HIV-positive participants to trial clinics for ART (fixed-dose combination of tenofovir, emtricitabine, and efavirenz) regardless of CD4 cell count (intervention) or according to national guidelines (initially ≤350 cells per μL and <500 cells per μL from January, 2015; control). Participants and investigators were not masked to treatment allocation. We used dried blood spots once every 6 months provided by participants who were HIV negative at baseline to estimate the primary outcome of HIV incidence with cluster-adjusted Poisson generalised estimated equations in the intention-to-treat population after 58 cluster-years of follow-up. This study is registered with ClinicalTrials.gov, number NCT01509508, and the South African National Clinical Trials Register, number DOH-27-0512-3974. Between March 9, 2012, and June 30, 2016, we contacted 26 518 (93%) of 28 419 eligible individuals. Of 17 808 (67%) individuals with a first negative dried blood spot test, 14 223 (80%) had subsequent dried blood spot tests, of whom 503 seroconverted after follow-up of 22 891 person-years. Estimated HIV incidence was 2·11 per 100 person-years (95% CI 1·84-2·39) in the intervention group and 2·27 per 100 person-years (2·00-2·54) in the control group (adjusted hazard ratio 1·01, 95% CI 0·87-1·17; p=0·89). We documented one case of suicidal attempt in a woman following HIV seroconversion. 128 patients on ART had 189 life-threatening or grade 4 clinical events: 69 (4%) of 1652 in the control group and 59 (4%) of 1367 in the intervention group (p=0·83). The absence of a lowering of HIV incidence in universal test and treat clusters most likely resulted from poor linkage to care. Policy change to HIV universal test and treat without innovation to improve health access is unlikely to reduce HIV incidence. ANRS, GiZ, and 3ie.

Design Issues in Transgender Studies.

:Transgender individuals constitute an important focus for HIV prevention, but studies in this population present some unique methodologic and operational challenges. We consider issues related to sampling, sample size, number of sites, and trial cost. We discuss relevant design issues for evaluating interventions in both HIV-negative and HIV-infected transgender populations, as well as a method for assessing the impact of an intervention on population HIV incidence. We find that HIV-endpoint studies of transgender individuals will likely require fewer participants but more sites and have higher operational costs than HIV prevention trials in other populations. Because any intervention targeted to transgender individuals will likely include antiretroviral drugs, small scale studies looking at potential interactions between antiretroviral therapy and hormone therapy are recommended. Finally, assessing the impact of an intervention targeted to transgender individuals will require better information on the contribution of such individuals to the population HIV incidence.

Predicting the Long-Term Impact of Antiretroviral Therapy Scale-Up on Population Incidence of Tuberculosis

ObjectiveTo investigate the impact of antiretroviral therapy (ART) on long-term population-level tuberculosis disease (TB) incidence in sub-Saharan Africa.MethodsWe used a mathematical model to consider the effect of different assumptions about life expectancy and TB risk during long-term ART under alternative scenarios for trends in population HIV incidence and ART coverage.ResultsAll the scenarios we explored predicted that the widespread introduction of ART would initially reduce population-level TB incidence. However, many modelled scenarios projected a rebound in population-level TB incidence after around 20 years. This rebound was predicted to exceed the TB incidence present before ART scale-up if decreases in HIV incidence during the same period were not sufficiently rapid or if the protective effect of ART on TB was not sustained. Nevertheless, most scenarios predicted a reduction in the cumulative TB incidence when accompanied by a relative decline in HIV incidence of more than 10% each year.ConclusionsDespite short-term benefits of ART scale-up on population TB incidence in sub-Saharan Africa, longer-term projections raise the possibility of a rebound in TB incidence. This highlights the importance of sustaining good adherence and immunologic response to ART and, crucially, the need for effective HIV preventive interventions, including early widespread implementation of ART.

Understanding the Potential Impact of a Combination HIV Prevention Intervention in a Hyper-Endemic Community

ObjectivesDespite demonstrating only partial efficacy in preventing new infections, available HIV prevention interventions could offer a powerful strategy when combined. In anticipation of combination HIV prevention programs and research studies we estimated the population-level impact of combining effective scalable interventions at high population coverage, determined the factors that influence this impact, and estimated the synergy between the components.MethodsWe used a mathematical model to investigate the effect on HIV incidence of a combination HIV prevention intervention comprised of high coverage of HIV testing and counselling, risk reduction following HIV diagnosis, male circumcision for HIV-uninfected men, and antiretroviral therapy (ART) for HIV-infected persons. The model was calibrated to data for KwaZulu-Natal, South Africa, where adult HIV prevalence is approximately 23%.ResultsCompared to current levels of HIV testing, circumcision, and ART, the combined intervention with ART initiation according to current guidelines could reduce HIV incidence by 47%, from 2.3 new infections per 100 person-years (pyar) to 1.2 per 100 pyar within 4 years and by almost 60%, to 1 per 100 pyar, after 25 years. Short-term impact is driven primarily by uptake of testing and reductions in risk behaviour following testing while long-term effects are driven by periodic HIV testing and retention in ART programs. If the combination prevention program incorporated HIV treatment upon diagnosis, incidence could be reduced by 63% after 4 years and by 76% (to about 0.5 per 100 pyar) after 15 years. The full impact of the combination interventions accrues over 10–15 years. Synergy is demonstrated between the intervention components.ConclusionHigh coverage combination of evidence-based strategies could generate substantial reductions in population HIV incidence in an African generalized HIV epidemic setting. The full impact could be underestimated by the short assessment duration of typical evaluations.

Determining HIV Incidence in Populations: Moving in the Right Direction

Determining HIV Incidence in Populations: Moving in the Right Direction

Health diplomacy and Adapting global health interventions to local needs: findings from project accept (HPTN 043), a community-based intervention to reduce HIV incidence in populations at risk in Sub-Saharan Africa and Thailand

Health diplomacy and Adapting global health interventions to local needs: findings from project accept (HPTN 043), a community-based intervention to reduce HIV incidence in populations at risk in Sub-Saharan Africa and Thailand

Statistical Considerations in Determining HIV Incidence from Changes in HIV Prevalence

The development of methods for estimating HIV incidence is critical for tracking the epidemic and for designing, targeting and evaluating HIV prevention efforts. One method for estimating incidence is based on changes in HIV prevalence. That method is attracting increased attention because national population-based HIV prevalence surveys, such as Demographic and Health Surveys, are being conducted throughout the world. Here, we consider some statistical issues associated with estimating HIV incidence from two population-based HIV prevalence surveys conducted at two different points in time. We show that the incidence estimator depends on the relative survival rate. We evaluate the sensitivity of estimates to incorrect assumptions about the relative survival rate, and show that small errors in the relative survival can, in some situations, create large biases in HIV incidence. We determine sample sizes of prevalence surveys to estimate incidence with precision and show how the sample sizes depend on baseline prevalence, the relative survival rate, and the population HIV incidence rate. We find that even if the relative survival rate were known exactly, there are situations where prohibitively large prevalence surveys would be required to produce reliable incidence estimates. These situations can occur either when the baseline prevalence is large, the relative survival rate is near 1, or the population incidence is small. Because information on the relative survival rate may be limited or not specific to the population under study, we suggest an approach to empirically estimate this critical parameter by augmenting population-based prevalence surveys with a mortality follow-up sub-study. We determine sample sizes of the prevalence surveys and mortality sub-studies for this augmented design and provide the necessary R code (version 2.13.0) for sample size determinations. We conclude that caution should be exercised when solely relying on changes in prevalence as the method for determining HIV incidence because of the method's sensitivity to mortality assumptions and the very large sample size requirements in some settings.

Beyond detuning: 10 years of progress and new challenges in the development and application of assays for HIV incidence estimation

Beyond detuning: 10 years of progress and new challenges in the development and application of assays for HIV incidence estimation

Antiretroviral treatment is a behavioural intervention: but why?

Antiretroviral treatment is a behavioural intervention: but why?

Mortality among HIV-positive postpartum women with high CD4 cell counts in Zimbabwe

Whereas HAART initiated at CD4 cell counts 351-450 cells/ml reduces mortality, compared with starting at lower CD4 levels, there is currently no evidence for the advantages of initiating treatment at CD4 cell counts greater than 450 cells/ml. Mortality hazard, as a function of CD4 cell count, was estimated among postpartum HIV-positive women in Zimbabwe, using HIV-negative women as the reference group. Mortality within 24 months postpartum was 54 times higher among women with CD4 cell counts less than 200 cells/ml, fell to 5.4 times higher for those with CD4 cell counts 400-600 cells/ml but fell little thereafter. For CD4 cell counts greater than 600 cells/ml the hazard was 6.2 (95% confidence interval 3.2-11.9). Early HAART initiation for all HIV-positive pregnant women may benefit individual mothers and infants, and simultaneously reduce population HIV incidence.

Project Accept (HPTN 043): A Community-Based Intervention to Reduce HIV Incidence in Populations at Risk for HIV in Sub-Saharan Africa and Thailand

Changing community norms to increase awareness of HIV status and reduce HIV-related stigma has the potential to reduce the incidence of HIV-1 infection in the developing world. We developed and implemented a multilevel intervention providing community-based HIV mobile voluntary counseling and testing, community mobilization, and posttest support services. Forty-eight communities in Tanzania, Zimbabwe, South Africa, and Thailand were randomized to receive the intervention or clinic-based standard voluntary counseling and testing (VCT), the comparison condition. We monitored utilization of community-based HIV mobile voluntary counseling and testing and clinic-based standard VCT by community of residence at 3 sites, which was used to assess differential uptake. We also developed quality assurance procedures to evaluate staff fidelity to the intervention. In the first year of the study, a 4-fold increase in testing was observed in the intervention versus comparison communities. We also found an overall 95% adherence to intervention components. Study outcomes, including prevalence of recent HIV infection and community-level HIV stigma, will be assessed after 3 years of intervention. The provision of mobile services, combined with appropriate support activities, may have significant effects on utilization of voluntary counseling and testing. These findings also provide early support for community mobilization as a strategy for increasing testing rates.

Population-level effect of HSV-2 therapy on the incidence of HIV in sub-Saharan Africa

Background:Herpes simplex virus type 2 (HSV-2) infection increases acquisition and transmission of HIV, but the results of trials measuring the impact of HSV-2 therapy on HIV genital shedding and HIV...

Use of the Serologic Testing Algorithm for Recent HIV Seroconversion (STARHS) to Identify Recently Acquired HIV Infections in Men With Early Syphilis in Los Angeles County

Syphilis outbreaks among men who have sex with men (MSM) in the United States, many of whom are HIV infected, have prompted increased concern for HIV transmission. To identify whether men are acquiring HIV concomitantly or within the critical period of syphilis infection, banked Treponema pallidum particle agglutination-positive serum specimens from men with early syphilis infection were screened for HIV-1 antibody. Samples that were positive for HIV antibody were then tested with a less sensitive (LS) HIV-1 antibody enzyme immunoassay (serologic testing algorithm for recent HIV seroconversion [STARHS]) to identify HIV infections that occurred on average within the previous 6 months. Of the 212 specimens banked from men with early syphilis, 74 (35%) were HIV-positive. Of these, 15 tested non-reactive by the LS assay. Twelve of these 15 were considered to be recent infections by the LS assay and testing history. Eleven (92%) of the recent infections were among MSM. One man had primary syphilis, 6 (50%) had secondary syphilis, and 5 (42%) had early latent syphilis. Eight men (67%) reported sex with anonymous partners, and 3 (25%) reported consistent condom use. The estimated HIV incidence was 17% per year (95% confidence interval [CI]: 12%-22%) among all men with early syphilis, and it was 26% per year (95% CI: 91%-33%) among MSM. Syphilis epidemics in MSM may be contributing to HIV incidence in this population. The STARHS can be applied as a surveillance tool to assess HIV incidence in various at-risk populations, but further studies are necessary for validation.

Management and Control of Sexually- transmitted Infections and their Implications for AIDS Control in South-East Asia

Sexually-transmitted infections (STIs) are highly prevalent in developing countries, including many parts of South-East Asia. The burden of diseuse due to these infections and their complications is enormous, particularly among women. STIs thus present a major public health problem in their own right. Accessible, affordable and effective treatment services need to be made available everywhere. The syndromic approach to STI diagnosis and case management based upon locally adapted standard treatment algorithm is byfarsuperiorto the presumptive clinical diagnostic approach that is still used in many parts of the region. This approach is particularly suitable in areas where efficient and affordable laboratory services are not available. STIs are known to enhance HIV transmission. Effective control of curable STIs has been shown to significantly reduce HIV incidence in popula tions. Such control measures should address all major steps of the Piot model: they should include primary prevention, screening to detect asymptomatic or neglected STI particularly among high- risk behaviour groups, and effertive treatment services for those who seek care forsymptomatic STI. So far the public health response to STI in South and South-East Asia has been varied. Some countries have addressed the problem quite vigorously, but most need to mount a much stronger coordinated response in the face of the accelerating HIV epidemic in the region. There is also a substantial need to systematically monitor and evaluate ongoing activities, including the quality of STI case management, and to make an attempt towards bridging the wide rift between policy and actual practices.