Calculate HIV Incidence Research Articles

Recent infection testing to inform HIV prevention responses and surveillance in a programme context: lessons from implementation within a nationally scaled female sex worker programme in Zimbabwe.

In the context of key population HIV testing programmes, identifying new HIV acquisitions, tracking incidence, and responding with prevention and treatment interventions will be critical for achieving HIV epidemic control. Laboratory tests for recently acquired HIV used as part of a "recent infection testing algorithm" (RITA), offer a potential tool to support this work. We implemented a RITA for female sex workers (FSWs) in Zimbabwe to explore opportunities and programmatic benefits. Between October 2021 and January 2023, recency testing was offered to FSWs attending the Centre for Sexual Health and HIV/AIDS Research (CeSHHAR) Zimbabwe's key populations programme. Dried blood spot (DBS) samples were taken at 86 clinic sites across 10 provinces and Laboratory LAg Avidity and viral load testing conducted. RITA results were analysed and linked to programme data to explore geographical differences and calculate HIV incidence. We describe concurrent efforts in HIV testing for social (social network testing [SNT]) and sexual (index case testing [ICT]) contacts of those testing HIV positive. Among 24,976 FSWs tested at programme sites, 9.5% (2363/24,976) were confirmed HIV positive. We enrolled 55.5% (1311/2363) of eligible HIV-positive FSWs to our study, of whom 11.7% (153/1311) were identified as having recently acquired HIV. It took a median of 37 days (IQR 20-67) for samples to be processed. Enrolment rates varied between provinces but the proportion of recently acquired HIV was similar (range: 18.4% to 4.0%). Overall HIV incidence was 3.4 (95% CI 2.7-4.0) per 100py. Where results could be linked to routinely collected data, we found no evidence of a difference in test-positivity between the ICT and SNT contacts of those with recently acquired compared to those with long-term HIV. Implementation of a RITA was possible within a nationally scaled sex worker programme, and while challenging to implement, can provide an understanding of transmission dynamics and HIV incidence in this context. Sub-optimal recruitment and data linkage limited the interpretation of our findings and opportunities for strategic gains though focusing on HIV prevention efforts.

HIV incidence in people receiving government-subsidised pre-exposure prophylaxis in Australia: a whole-of-population retrospective cohort study

HIV pre-exposure prophylaxis (PrEP) is highly effective and has been government subsidised in Australia since April, 2018. We examined HIV incidence over 5 years in a retrospective observational cohort of people who had received subsidised PrEP. Linked de-identified dispensing records for all government-subsidised oral PrEP, HIV antiretroviral therapy (ART), and hepatitis C treatment were used. We included all people dispensed subsidised PrEP from April 1, 2018, to March 31, 2023, and examined records up to Sept 30, 2023. Exposure was measured from date of first PrEP prescription and days covered by PrEP calculated for individuals based on quantity and date supplied. Assuming that HIV was diagnosed 30 days before ART initiation, we imputed the date of acquisition as the midpoint between the diagnosis and the later of the last PrEP prescription or 6 months before the diagnosis. We calculated HIV incidence and its predictors using Poisson regression. We included 66 206 people dispensed PrEP: 64 757 (97·8%) were men; median age was 33 years (IQR 27-43). 207 people acquired HIV, with an overall incidence of 1·07 per 1000 person-years (95% CI 0·93-1·23). Incidence was 2·61 per 1000 person-years among those dispensed PrEP once only. Using this group as a comparator, those with 60% or more days covered by PrEP had a 78·5% reduction in incidence (0·56 per 1000 person-years, p<0·0001) and those with less than 60% days covered had a 61·6% reduction (0·99 per 1000 person-years, p=0·0045). Independent predictors of HIV acquisition were a record of hepatitis C treatment (9·83 per 1000 person-years, adjusted incident rate ratio [aIRR] 8·70, 95% CI 4·86-15·56), only attending prescribers outside of areas with a high estimated prevalence of gay men (1·66 per 1000 person-years, aIRR 1·50, 1·08-2·09), age 18-29 years (1·33 per 1000 person-years, aIRR 1·56, 1·11-2·21), and earlier year of first PrEP. The low observed incidence of HIV among people receiving government-subsidised PrEP highlights the success of a national programme of oral PrEP scale-up in achieving sustained reduction in community HIV transmission. However, incidence varied greatly, indicating that more research is needed to understand why people were not taking PrEP at times of risk and emphasising the need for new interventions focused on this population to achieve elimination of HIV transmission. Individuals dispensed PrEP once only and less frequent users might benefit from more support. None.

Staged HIV transmission and treatment in a dynamic model with long-term partnerships

The transmission dynamics of HIV are closely tied to the duration and overlap of sexual partnerships. We develop an autonomous population model that can account for the possibilities of an infection from either a casual sexual partner or a long-term partner who was either infected at the start of the partnership or has been newly infected since the onset of the partnership. The impact of the long-term partnerships on the rate of infection is captured by calculating the expected values of the rate of infection from these extended contacts. The model includes three stages of infectiousness: acute, chronic, and virally suppressed. We calculate HIV incidence and the fraction of new infections attributed to casual contacts and long-term partnerships allowing for variability in condom usage, the effect of achieving and maintaining viral suppression, and early intervention by beginning HAART during the acute phase of infection. We present our results using data on MSM HIV transmission from the CDC in the U.S. While the acute stage is the most infectious, the majority of the new infections will be transmitted by long-term partners in the chronic stage when condom use is infrequent as is common in long-term relationships. Time series analysis of the solution, as well as parameter sensitivity analysis, are used to determine effective intervention strategies.

Providing HIV pre-exposure prophylaxis to men who have sex with men and transgender women in hospitals and community-led clinics in Thailand: acceptance, patterns of use, trends in risk behaviors, and HIV incidence

ABSTRACT From May 2015 to June 2018, we conducted a PrEP demonstration project at two hospitals and four community-led clinics in Bangkok and Pattaya. HIV-negative, MSM and TGW aged ≥18 years old, reporting sex without a condom, were offered daily PrEP. Participants received HIV testing and completed a computer-based questionnaire at enrollment, 6 and 12 months. We collected self-reported PrEP adherence at months 1, 3, 6, 9, and 12. We used logistic regression to determine factors associated with the decision to take PrEP and calculated HIV incidence among baseline HIV-negative participants. Of 803 participants enrolled, 349 (43.5%) started PrEP. Participants were more likely to start PrEP if they were sex workers, had moderate or high self-perceived risk of HIV, or a high PrEP-knowledge score. Participants used PrEP for a median of 6.1 months. Reported condom use increased and the number of sex partners decreased during follow-up regardless of PrEP use. Six participants not-taking PrEP acquired HIV (HIV incidence 2.2 per 100 person-years), and five taking PrEP acquired HIV (HIV incidence 2.1 per 100 person-years). All five reported taking <4 pills the weeks before study visits.

Incident HIV acquisition among pregnant women in Botswana: findings from the Tsepamo birth outcomes surveillance study.

In Botswana, where almost all pregnant women known to have HIV receive antiretroviral therapy, a large proportion of vertical HIV transmission may occur among women with incident undiagnosed HIV infection during pregnancy. Botswana guidelines recommend repeat HIV testing every 3 months in pregnancy, with at least one test in the third trimester. We evaluated the rate of repeat HIV testing, calculated HIV incidence during pregnancy and estimated missed seroconversions. In the Botswana Tsepamo Study, we abstracted HIV test dates and results from obstetric records of all women who delivered at maternity wards in 18 communities between 7th May 2017 and 20th August 2021. We defined seroconversion as an initial negative/indeterminate HIV test in pregnancy followed by a positive test during pregnancy/at delivery. The incidence rate (IR) of seroconversion was calculated among women with > = 2 known test dates. Missed seroconversions were estimated among women without a test in the third trimester by applying the IR to the time after the last HIV test until delivery. Among 103,529 women delivering in the study period testing negative at the first test and with known conception and HIV test dates, 29,085 (28%) were tested in one trimester of pregnancy, 73,156 (71%) were tested in ≥2 trimesters of pregnancy and 9628 (9%) had a test in all trimesters. A total of 78,162 (75%) women had a third-trimester test. There were 223 seroconversions (2.58/1000 pregnancies, 0.26%) among those with ≥2 known HIV test dates, yielding an IR of 0.69/100 person-years. Among 25,289 women who did not have a test in the third trimester, we estimate approximately 58 seroconversions may have been missed during pregnancy due to a lack of repeat testing. Factors associated with seroconversion during pregnancy included younger age, less education and not being married. More than two-thirds of women had repeat HIV testing in pregnancy and HIV incidence was low. However, an estimated 21% of seroconversions in pregnancy were likely missed due to a lack of re-testing. To reach the goal of zero new paediatric HIV infections, Botswana will need to intensify repeat HIV testing in the third trimester of pregnancy.

Estimation of HIV incidence from analysis of HIV prevalence patterns among female sex workers in Zimbabwe.

To estimate HIV incidence among female sex workers (FSW) in Zimbabwe: using HIV prevalence by age and number of years since started selling sex (YSSS). We pooled data from FSW aged 18-39 participating in respondent-driven sampling surveys conducted in Zimbabwe between 2011 and 2017. For each year of age, we estimated: HIV prevalence ( Pt ) and the change in HIV prevalence from the previous age ( Pt - Pt -1 ). We then estimated the rate of new HIV infections during that year of age: It = Pt - Pt -1 /(1 - Pt -1 ), and calculated HIV incidence for 18-24 and 25-39 year-olds separately as the weighted average of It . We estimated HIV incidence for FSW 1-5 years and 6-15 years since first selling sex using the same approach, and compared HIV prevalence among FSW first selling sex at their current age with the general population. Among 9906 women, 50.2% were HIV positive. Based on HIV prevalence increases by age, we estimated an HIV incidence of 6.3/100 person-years at risk (pyar) (95% confidence interval [CI] 5.3, 7.6) among 18-24 year-olds, and 3.3/100 pyar (95% CI 1.3, 4.2) among 25-39 year-olds. Based on prevalence increases by YSSS, HIV incidence was 5.3/100 pyar (95% CI 4.3, 8.5) between 1 and 5 years since first selling sex, and 2.1/100 pyar (95% CI -1.3, 7.2) between 6 and 15 years. Our analysis is consistent with very high HIV incidence among FSW in Zimbabwe, especially among those who are young and recently started selling sex. There is a critical need to engage young entrants into sex work in interventions that reduce their HIV risk.

866. Adherence to F/TDF for PrEP in Dried Blood Spots and HIV Infection Rates: A Pooled Analysis of Global PrEP Studies

BackgroundThe use of daily F/TDF for HIV pre-exposure prophylaxis (PrEP) substantially reduces HIV acquisition. Dried blood spot (DBS) tenofovir-diphosphate (TFV-DP) levels reflect TDF use over the past 6-8 weeks, providing an objective measure of adherence in people taking PrEP.MethodsIn a pooled analysis of 19 PrEP demonstration projects and clinical studies, 6,613 participants had at least one TFV-DP measurement in DBS and followed for at least 48 weeks and up to 96 weeks. We used a piecewise linear mixed-effects model to plot the least-square means with corresponding 95% confidence intervals (CI) of TFV-DP for adherence over time, and Poisson regressions to calculate HIV incidence rates (IR) by level of weighted average of TFV-DP.ResultsOf 6,613 participants, median age was 30 years (interquartile range 24−38), 5,449 (82%) were cisgender men, 806 (12%) were cisgender women, and 349 (5%) were transgender (316 transgender women, 2 transgender men, 31 unspecified). Adherence based on TFV-DP in DBS was consistently higher among participants who did not acquire HIV compared to those who did (Figure). Among all participants, 21%, 14%, 36%, and 29% has DBS consistent with taking < 2, 2−3, 4−6, and ≥7 tablets of F/TDF PrEP per week (Table). Sixty-nine participants acquired HIV, with a median PrEP exposure of 0.82 years and an overall HIV IR (95% CI) of 1.16 (0.92, 1.47) per 100 person years. There was a strong association between adherence and HIV incidence [among individuals who took < 2, 2−3, 4−6, and ≥7 tablets/week, the HIV IRs (95% CI) were 5.20 (4.03, 6.71), 0.38 (0.12, 1.18), 0.28 (0.12, 0.61), and 0.06 (0.01, 0.39), respectively. Overall IR (95% CI) of HIV infection among cisgender men was 1.25 (0.98, 1.60) per 100 patient-years. Four cisgender women and 2 transgender participants acquired HIV, corresponding to IRs (95% CI) of 0.71 (0.27, 1.90) and 0.63 (0.16, 2.53).Adherence by TFV-DP in DBS for F/TDF users who acquired HIV compared to those who did not. Note: ‘x’ on the Figure represents visit week when a new HIV infection was detected.HIV incidence rates (95% confidence intervals) by adherence to PrEP measured by level of TFV-DP in DBS up to 96 weeks after PrEP Initiation ConclusionThis diverse, multi-national pooled analysis of F/TDF PrEP use provides the largest assessment to date of the adherence-HIV incidence relationship in people taking F/TDF for PrEP. The results suggest a high background HIV incidence in the pooled cohort and high efficacy in those adherent to PrEP. These findings support ongoing efforts to increase PrEP use among people who would benefit.Disclosures Albert Liu, MD, MPH, Gilead Sciences (Individual(s) Involved: Self): Gilead has donated study drug for studies I have led., Grant/Research Support, Other Financial or Material Support, Research Grant or Support; IAS-USA (Individual(s) Involved: Self): Honorarium for manuscript writing, Other Financial or Material Support; Viiv Healthcare (Individual(s) Involved: Self): Grant/Research Support, Research Grant or Support Raphael J. Landovitz, MD, MSc, Gilead Sciences (Individual(s) Involved: Self): Consultant; Janssen (Individual(s) Involved: Self): Consultant; Merck Inc (Individual(s) Involved: Self): Consultant; Roche (Individual(s) Involved: Self): Consultant Jared Baeten, MD, PHD, Gilead Sciences Inc. (Employee, Shareholder) David Magnuson, PharmD, Gilead Sciences Inc (Employee, Shareholder) Moupali Das, MD, Gilead Sciences Inc. (Employee, Shareholder) Christoph C. Carter, MD, Gilead Sciences Inc. (Employee, Shareholder) Li Tao, MD, PhD, Gilead Sciences Inc (Employee, Shareholder)

Risk Factors for HIV sero-conversion in a high incidence cohort of men who have sex with men and transgender women in Bangkok, Thailand.

BackgroundWe measured Human Immunodeficiency (HIV) incidence, retention, and assessed risk factors for seroconversion among two previously unreported cohorts of men who have sex with men (MSM) and Transgender Women (TGW) in Bangkok, Thailand between 2017 and 2019.MethodsWe conducted an 18-month prospective cohort study of HIV-uninfected Thai cisgender men and TGW aged between 18 and 35 years who reported sex with men in the past six months and at least one additional risk factor for HIV infection. HIV and syphilis testing and computer-based behavioral questionnaires were administered at each visit. We utilized Poisson regression to calculate HIV incidence rates. A survival random forest model identified the most predictive risk factors for HIV sero-conversion and then used in a survival regression tree model to elucidate hazard ratios for individuals with groups of selected risk factors. Cox proportional hazards (pH) regression evaluated the strength of association between individual covariates and risk of sero-conversion.FindingsFrom April 2017-October 2019, 1,184 participants were screened, 167 were found ineligible, and 1,017 enrolled. Over the 18-month study, visit retention was 93·4% (95% CI 91·6%–94·8%) and HIV incidence was 3·73 per 100 person-years (95% CI 2·79–5·87). Utilizing survival regression tree modeling, those who were 18–20 years of age, reported sexual attraction to mostly or only men, and had five or more lifetime sexual partners were 4·9 times more likely to seroconvert compared to other cohort participants. Factors associated with HIV incidence utilizing Cox pH regression included sexual attraction to mostly or only men (adjusted hazard ratio (aHR) 14·9 (95% CI 20·1–107·9), younger age (18–19 years, aHR 10·88 (95% CI 4·12–28·7), five or greater lifetime sexual partners (aHR 2·0, 95%CI 1·1–3·6), inconsistent condom use with casual partners (aHR 2·43, 95% CI 1·3–4·5), and prior HIV testing (adjusted HR 2·0, 95% CI 1·1–3·5).InterpretationInterpretation HIV incidence remains high among Bangkok-based MSM and TGW. These key populations expressed high interest in participating in efficacy evaluation of future prevention strategies and had high retention in this 18 month study.FundingFunding US National Institute of Allergy and Infectious Diseases (NIAID), Division of AIDS Interagency Agreements (DAIDS) and U.S. Department of the Army.

Risk Factors for HIV Seroconversion in a High Incidence Cohort of Men Who Have Sex with Men and Transgender Women in Bangkok, Thailand

Background: In order to assess feasibility for future HIV prevention trials, we measured HIV incidence, retention, and assessed risk factors for seroconversion among men who have sex with men (MSM) and transgender women (TGW) in Bangkok, Thailand between 2017-2019. Methods: We conducted an 18-month prospective cohort study of HIV-uninfected Thai cisgender men and transgender women who reported sex with men in the past six months. HIV and syphilis testing and computer-based behavioral questionnaires were administered at each visit. We utilized Poisson regression to calculate HIV incidence rates. A survival random forest model identified the most predictive risk factors for HIV seroconversion and then used in a survival regression tree model to elucidate hazard ratios for individuals with groups of selected risk factors. Cox proportional hazards (PH) regression evaluated the strength of association between individual covariates and risk of seroconversion. Findings: From April 2017-October 2019, 1,184 participants were screened, 167 were found ineligible, and 1,017 enrolled. Over the 18-month study, visit retention was 93·4% (95% CI 91·6%-94·8%) and HIV incidence was 3·73 per 100 person-years (95% CI 2·79-5·87). Utilizing survival regression tree modeling, those who were 18-20 years of age, reported sexual attraction to mostly or only men, and had five or more lifetime sexual partners were 4·9 times more likely to seroconvert compared to other cohort participants. Factors associated with HIV incidence utilizing Cox PH regression included sexual attraction to mostly or only men (adjusted hazard ratio (aHR) 14·9 (95% CI 20·1-107·9), younger age (18-19 years, aHR 10·88 (95% CI 4·12-28·7), five or greater lifetime sexual partners (aHR 2·0, 95%CI 1·1-3·6), inconsistent condom use with casual partners (aHR 2·43, 95% CI 1·3-4·5), and prior HIV testing (adjusted HR 2·0, 95% CI 1·1-3·5). Interpretation: HIV incidence remains high among Bangkok-based MSM and TGW. These key populations have high retention and are ideal candidates for efficacy evaluation of future prevention strategies. Funding Statement: This work was supported by the US Army Medical Research and Materiel Command (Military Infectious Diseases Research Program) (cooperative agreements W81XWH-11-2-0174 and W81XWH-07-2-0067 with the Henry M. Jackson Foundation for the Advancement of Military Medicine), the US Army Medical Materiel Development Activity, and the National Institute of Allergy and Infectious Disease (interagency agreement Y1-AI-2642-12 with the US Army Medical Research and Materiel Command) and the Division of AIDS Interagency Agreements (DAIDS IAA Y1-AI-2642-16). Declaration of Interests: T.C. reports grants from U.S. Army, grants from NIH, M.R. and S.V. reports grants from US Army Medical Research and Materiel Command with Henry M. Jackson Foundation for the Advancement of Military Medicine, during the conduct of the study. All other authors report no potential conflicts. Ethics Approval Statement: The study was reviewed and approved by the institutional review boards at Walter Reed Army Institute of Research (WRAIR), Faculty of Tropical Medicine at Mahidol University, and the Royal Thai Army. All participants provided written informed consent prior to enrollment.

Sexual Behavior Among Men Who Have Sex With Men: The Need for More Targeted Outreach to Men Who Also Have Sex With Cisgender Women.

In Peru, as in the Americas overall, men who have sex with men (MSM) are disproportionately affected by HIV. Most research focuses on practices between cisgender men, whereas many MSM report male and female partners, cisgender, transgender, or both. Data for these analyses were from a treatment-as-prevention study in Lima (the Sabes study). We compared demographics and behaviors of MSM who reported cisgender women partners in the past 3 months (MSMW) and MSM who reported both cisgender and transgender women partners (MSMW-T) to MSM who reported only male partners (MSMO). We calculated HIV incidence in each group during 2-year follow-up. Compared with MSMO, MSMW and MSMW-T more often self-identify as heterosexual or bisexual and report insertive sex practices. MSMW reported condomless sex with cisgender women: vaginal (72%), anal sex (18%). One-third of MSMW reported condomless receptive anal sex with men in the past 3 months, with 24% of MSMW overall who reported both condomless receptive sex with men and condomless insertive vaginal or anal sex with cisgender women. Of these, 17% were HIV infected. HIV incidence did not differ significantly between groups. Most MSMW and MSMW-T report bisexual or heterosexual orientation and prefer insertive sex. MSMW and MSMW-T (47% and 29%, respectively) engage in receptive anal intercourse. In both groups, the majority who engaged in condomless receptive sex with men (76% MSMW, 85% MSMW-T) also engaged in condomless vaginal and/or anal sex with women, indicating need for intervention.

Development of a Mathematical Model to Estimate the Cost-Effectiveness of HRSA's Ryan White HIV/AIDS Program.

The Health Resources and Services Administration's Ryan White HIV/AIDS Program provides services to more than half of all people diagnosed with HIV in the United States. We present and validate a mathematical model that can be used to estimate the long-term public health and cost impact of the federal program. We developed a stochastic, agent-based model that reflects the current HIV epidemic in the United States. The model simulates everyone's progression along the HIV care continuum, using 2 network-based mechanisms for HIV transmission: injection drug use and sexual contact. To test the validity of the model, we calculated HIV incidence, mortality, life expectancy, and lifetime care costs and compared the results with external benchmarks. The estimated HIV incidence rate for men who have sex with men (502 per 100,000 person years), mortality rate of all people diagnosed with HIV (1663 per 100,000 person years), average life expectancy for individuals with low CD4 counts not on antiretroviral therapy (1.52-3.78 years), and lifetime costs ($362,385) all met our validity criterion of within 15% of external benchmarks. The model represents a complex HIV care delivery system rather than a single intervention, which required developing solutions to several challenges, such as calculating need for and receipt of multiple services and estimating their impact on care retention and viral suppression. Our strategies to address these methodological challenges produced a valid model for assessing the cost-effectiveness of the Ryan White HIV/AIDS Program.

Rates and Correlates of HIV Incidence in Namibia's Zambezi Region From 2014 to 2016: Sentinel, Community-Based Cohort Study.

BackgroundDirect measures of HIV incidence are needed to assess the population-level impact of prevention programs but are scarcely available in the subnational epidemic hotspots of sub-Saharan Africa. We created a sentinel HIV incidence cohort within a community-based program that provided home-based HIV testing to all residents of Namibia’s Zambezi region, where approximately 24% of the adult population was estimated to be living with HIV.ObjectiveThe aim of this study was to estimate HIV incidence, detect correlates of HIV acquisition, and assess the feasibility of the sentinel, community-based approach to HIV incidence surveillance in a subnational epidemic hotspot.MethodsFollowing the program’s initial home-based testing (December 2014-July 2015), we purposefully selected 10 clusters of 60 to 70 households each and invited residents who were HIV negative and aged ≥15 years to participate in the cohort. Consenting participants completed behavioral interviews and a second HIV test approximately 1 year later (March-September 2016). We used Poisson models to calculate HIV incidence rates between baseline and follow-up and multivariable Cox proportional hazard models to assess the correlates of seroconversion.ResultsAmong 1742 HIV-negative participants, 1624 (93.23%) completed follow-up. We observed 26 seroconversions in 1954 person-years (PY) of follow-up, equating to an overall incidence rate of 1.33 per 100 PY (95% CI 0.91-1.95). Among women, the incidence was 1.55 per 100 PY (95% CI 1.12-2.17) and significantly higher among those aged 15 to 24 years and residing in rural areas (adjusted hazard ratio [aHR] 4.26, 95% CI 1.39-13.13; P=.01), residing in the Ngweze suburb of Katima Mulilo city (aHR 2.34, 95% CI 1.25-4.40; P=.01), who had no prior HIV testing in the year before cohort enrollment (aHR 3.38, 95% CI 1.04-10.95; P=.05), and who had engaged in transactional sex (aHR 17.64, 95% CI 2.88-108.14; P=.02). Among men, HIV incidence was 1.05 per 100 PY (95% CI 0.54-2.31) and significantly higher among those aged 40 to 44 years (aHR 13.04, 95% CI 5.98-28.41; P<.001) and had sought HIV testing outside the study between baseline and follow-up (aHR 8.28, 95% CI 1.39-49.38; P=.02). No seroconversions occurred among persons with HIV-positive partners on antiretroviral treatment.ConclusionsNearly three decades into Namibia’s generalized HIV epidemic, these are the first estimates of HIV incidence for its highest prevalence region. By creating a sentinel incidence cohort from the infrastructure of an existing community-based testing program, we were able to characterize current transmission patterns, corroborate known risk factors for HIV acquisition, and provide insight into the efficacy of prevention interventions in a subnational epidemic hotspot. This study demonstrates an efficient and scalable framework for longitudinal HIV incidence surveillance that can be implemented in diverse sentinel sites and populations.

Missed opportunities to prevent HIV infections among pre-exposure prophylaxis users: a population-based mixed methods study, San Francisco, United States.

IntroductionPre‐exposure prophylaxis (PrEP) is highly effective, although PrEP adherence and persistence has been variable during real world implementation. Little is known about missed opportunities to enhance PrEP adherence among individuals who later HIV seroconverted after using PrEP. The goal of this analysis was to identify all HIV infections among individuals who had accessed PrEP in an integrated health system in San Francisco, and to identify potentially intervenable factors that could have prevented HIV infection through in‐depth interviews with people who HIV seroconverted after using PrEP.MethodsWe identified individuals who initiated PrEP in an integrated safety‐net public health system and performed in‐depth chart review to determine person‐time on and after stopping PrEP over six years. We identified all PrEP seroconversions using the Centers for Disease Control and Prevention’s Enhanced HIV/AIDS Reporting System and then calculated HIV incidence while using PrEP and during gaps in use. We then performed in‐depth interviews with those who seroconverted.ResultsOverall, 986 initiated PrEP across the San Francisco Department of Public Health from July 2012 to November 2018. Data were gathered from 895 person‐years on PrEP and 953 after stopping PrEP. The HIV incidence was 7.5‐fold higher after stopping PrEP compared to while on PrEP (95% CI 1 to 336). Of the eight individuals who HIV seroconverted; only one was taking PrEP at the time of seroconversion but was using on‐demand PrEP inconsistently. All eight agreed to qualitative interviews. Major barriers to PrEP persistence included substance use, mental health and housing loss; difficulty accessing PrEP due to cost, insurance, and the cost and time of medical visits; difficulty weighing PrEP’s benefit versus self‐perceived risk; and entering a primary partnership. The individual who developed HIV using on‐demand PrEP reported confusion about the dosing regimen and which sexual encounters required accompanying PrEP dosing.ConclusionsHIV incidence during gaps in PrEP use was nearly eight‐fold higher than while on PrEP in this large cohort in San Francisco. Many individuals who stop PrEP remain at risk of HIV, and participants reported that proactive outreach could potentially have prevented HIV infections. Individuals using non‐daily PrEP may require additional education and support in the United States.

Mind the gaps: prescription coverage and HIV incidence among patients receiving pre-exposure prophylaxis from a large federally qualified health center in Los Angeles, California : Mind the Gaps:Cobertura de recetas e incidencia de VIH entre pacientes recibiendo profilaxis pre-exposiciónde un centro de salud grande y federalmente calificadoen Los Ángeles, CA.

We conducted a records-based cohort study of patients who initiated pre-exposure prophylaxis (PrEP) at a large federally qualified health center in Los Angeles, CA to characterize patterns of PrEP use, identify correlates of PrEP discontinuation, and calculate HIV incidence. Of 3121 individuals initiating PrEP between 2014 and 2017, 42% (n = 1314) were active (i.e., had a current PrEP prescription) in April 2018. HIV incidence was 0.1/100 person-years among active PrEP patients, compared to 2.1/100 person-years among patients who discontinued. Compared to patients accessing PrEP through government programs with no prescription copay, risk of discontinuation was higher among those with private insurance (ARR = 1.4, 95% CI 1.2, 1.7), or no insurance (ARR = 4.5, 95% CI 3.2, 6.4). Sixty-three percent of active PrEP patients had gaps between PrEP prescriptions, averaging one gap per year (median length = 65days). Increasing access to free or low-cost PrEP can improve PrEP continuity.

Risk of sexual transmission of human immunodeficiency virus with antiretroviral therapy, suppressed viral load and condom use: a systematic review

The Public Health Agency of Canada reviewed sexual transmission of HIV between serodiscordant partners to support examination of the criminal justice system response to HIV nondisclosure by the Department of Justice of Canada. We sought to determine HIV transmission risk when an HIV-positive partner takes antiretroviral therapy, has a suppressed viral load or uses condoms. We conducted an overview and systematic review update by searching MEDLINE and other databases (Jan. 1, 2007, to Mar. 13, 2017; and Nov. 1, 2012, to Apr. 27, 2017, respectively). We considered reviews and studies about absolute risk of sexual transmission of HIV between serodiscordant partners to be eligible for inclusion. We used A Measurement Tool to Assess Systematic Reviews (AMSTAR) for review quality, Quality in Prognosis Studies (QUIPS) instrument for study risk of bias and then the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach to assess the quality of evidence across studies. We calculated HIV incidence per 100 person-years with 95% confidence intervals (CIs). We assigned risk categories according to potential for and evidence of HIV transmission. We identified 12 reviews. We selected 1 review to estimate risk of HIV transmission for condom use without antiretroviral therapy (1.14 transmissions/100 person-years, 95% CI 0.56-2.04; low risk). We identified 11 studies with 23 transmissions over 10 511 person-years with antiretroviral therapy (0.22 transmissions/ 100 person-years, 95% CI 0.14-0.33; low risk). We found no transmissions with antiretroviral therapy and a viral load of less than 200 copies/mL across consecutive measurements 4 to 6 months apart (0.00 transmissions/100 person-years, 95% CI 0.00-0.28; negligible risk regardless of condom use). Based on high-quality evidence, there is a negligible risk of sexual transmission of HIV when an HIV-positive sex partner adheres to antiretroviral therapy and maintains a suppressed viral load of less than 200 copies/mL measured every 4 to 6 months. Sexual transmissions of HIV have occurred when viral load was more than 200 copies/mL with antiretroviral therapy or condoms alone were used, although the risk remains low. These findings will help to support patient and clinician decision-making, affect public health case management and contact tracing, and inform justice system responses to HIV nondisclosure.

Implementation and assessment of a model to increase HIV testing among men who have sex with men and transgender women in Thailand, 2011–2016

ABSTRACTHIV testing among men who have sex with men (MSM) and transgender (TG) women remains low in Thailand. The HIV prevention program (PREV) to increase HIV testing and link those who tested HIV-positive to care provided trainings to peer educators to conduct target mapping, identify high risk MSM and TG women through outreach education and offer them rapid HIV testing. Trained hospital staff provided HIV testing and counseling with same-day results at hospitals and mobile clinics and referred HIV-positive participants for care and treatment. We used a standardized HIV pre-test counseling form to collect participant characteristics and analyzed HIV test results using Poisson regression and Wilcoxon rank sum trend tests to determine trends over time. We calculated HIV incidence using data from participants who initially tested HIV-negative and tested at least one more time during the program. Confidence intervals for HIV incidence rates were calculated using the Exact Poisson method.From September 2011 through August 2016, 5,629 participants had an HIV test; their median age was 24 years, 1,923 (34%) tested at mobile clinics, 5,609 (99.6%) received their test result, and 1,193 (21%) tested HIV positive. The number of people testing increased from 458 in 2012 to 1,832 in 2016 (p < 0.001). Participants testing at mobile clinics were younger (p < 0.001) and more likely to be testing for the first time (p < 0.001) than those tested at hospitals. Of 1,193 HIV-positive participants, 756 (63%) had CD4 testing. Among 925 participants who returned for HIV testing, HIV incidence was 6.2 per 100 person-years. Incidence was highest among people 20–24 years old (10.9 per 100 person-years).HIV testing among MSM and TG women increased during the PREV program. HIV incidence remains alarmingly high especially among young participants. There is an urgent need to expand HIV prevention services to MSM and TG women in Thailand.

Mind the Gaps: Prescription Coverage and HIV Incidence Among Patients Receiving Pre-Exposure Prophylaxis from a Large Federally Qualified Health Center in Los Angeles, California

Background: Understanding long-term, real world use of pre-exposure prophylaxis (PrEP) is key to improving HIV prevention. The few previous studies on PrEP continuation in community settings have identified retention as a major challenge, but data on how episodic access to PrEP affects HIV incidence has been sparse. Methods: We conducted a records-based cohort study of patients who initiated PrEP at a large federally qualified health center in Los Angeles, CA between January 2014 and December 2017. We characterized patterns of episodic PrEP use, identified correlates of PrEP discontinuation, and calculated HIV incidence. Results: Of 3,121 individuals who initiated PrEP, 42% (n=1,314) were active (i.e., had a current PrEP prescription) at the end of the analysis period. Of these, 63% (n=829) had gaps between PrEP prescriptions, averaging one gap per year (median gap length = 65 days, interquartile range = 37-129 days). HIV incidence was 0.1 cases per 100 person-years among active PrEP patients, compared to 2.1 cases per 100 person-years among patients who discontinued PrEP. Patients aged 18-24 had higher risk of discontinuation (Adjusted rate ratio (ARR) =2.8, 95% confidence interval (CI): 1.9, 4.0) compared to those aged 41-50. Compared to patients accessing PrEP through government programs with no prescription copay, risk of discontinuation was significantly higher among those with private insurance (ARR = 1.4, 95% CI: 1.2, 1.7), and those with no insurance (ARR = 4.5, 95% CI 3.2, 6.4). Conclusions: Increasing access to free or low-cost PrEP can maximize PrEP's effectiveness at reducing HIV transmission in community settings. Efforts to support PrEP continuation among young people are warranted. Funding Statement: MJ was supported by the National Institutes of Health and National Institute of Allergy and Infectious Disease, grant number K01AI091861. MRB was supported by the UCLA Postdoctoral Fellowship Training Program in Global HIV Prevention Research (Currier and Gorbach, PIs); T32MH080634. Declaration of Interests: The authors declare that there are none to report. Ethics Approval Statement: The study was approved by the Institutional Review Board at the University of California, Los Angeles (IRB#17-000717).

High HIV incidence among young black men who have sex with men: constructing a retrospective cohort from a community health programme

ObjectivesWe sought to calculate HIV incidence in a retrospective cohort of young (13–29 years old) black men who have sex with men (YBMSM) accessing repeated HIV-antibody testing in a mid-size...

Swaziland HIV Incidence Measurement Survey (SHIMS): a prospective national cohort study

Swaziland has the highest national HIV prevalence worldwide. The Swaziland HIV Incidence Measurement Survey (SHIMS) provides the first national HIV incidence estimate based on prospectively observed HIV seroconversions. A two-stage survey sampling design was used to select a nationally representative sample of men and women aged 18-49 years from 14 891 households in 575 enumeration areas in Swaziland, who underwent household-based counselling and rapid HIV testing during 2011. All individuals aged 18-49 years who resided or had slept in the household the night before and were willing to undergo home-based HIV testing, answer demographic and behavioural questions in English or siSwati, and provide written informed consent were eligible for the study. We performed rapid HIV testing and assessed sociodemographic and behavioural characteristics with use of a questionnaire at baseline and, for HIV-seronegative individuals, 6 months later. We calculated HIV incidence with Poisson regression modelling as events per person-years × 100, and we assessed covariables as predictors with Cox proportional hazards modelling. Survey weighting was applied and all models used survey sampling methods. Between Dec 10, 2010, and June 25, 2011, 11 897 HIV-seronegative adults were enrolled in SHIMS and 11 232 (94%) were re-tested. Of these, 145 HIV seroconversions were observed, resulting in a weighted HIV incidence of 2·4% (95% CI 2·1-2·8). Incidence was nearly twice as high in women (3·1%; 95% CI 2·6-3·7) as in men (1·7%; 1·3-2·1, p<0·0001). Among men, partner's HIV-positive status (adjusted hazard ratio [aHR] 2·67, 1·06-6·82, p=0·040) or unknown serostatus (aHR 4·64, 2·32-9·27, p<0·0001) in the past 6 months predicted HIV seroconversion. Among women, significant predictors included not being married (aHR 2·90, 1·44-5·84, p=0·0030), having a spouse who lives elsewhere (aHR 2·66, 1·29-5·45, p=0·0078), and having a partner in the past 6 months with unknown HIV status (aHR 2·87, 1·44-5·84, p=0·0030). Swaziland has the highest national HIV incidence in the world. In high-prevalence countries, population-based incidence measures and programmes that further expand HIV testing and support disclosure of HIV status are needed. President's Emergency Plan for AIDS Relief (PEPFAR) by the Centers for Disease Control and Prevention.

High and persistent HIV seroincidence in men who have sex with men across 47 U.S. cities.

ObjectiveTo provide HIV seroincidence data among men who have sex with men (MSM) in the United States and to identify predictive factors for seroconversion.MethodsFrom 1998–2002, 4684 high-risk MSM, age 18–60 years, participated in a randomized, placebo-controlled HIV vaccine efficacy trial at 56 U.S. clinical trial sites. Demographics, behavioral data, and HIV status were assessed at baseline and 6 month intervals. Since no overall vaccine efficacy was detected, data were combined from both trial arms to calculate HIV incidence based on person-years (py) of follow-up. Predictors of seroconversion, adjusted hazards ratio (aHR), were evaluated using a Cox proportional hazard model with time-varying covariates.ResultsOverall, HIV incidence was 2.7/100 py and was relatively uniform across study sites and study years. HIV incidence was highest among young men and men reporting unprotected sex, recreational drug use, and a history of a sexually transmitted infection. Independent predictors of HIV seroconversion included: age 18–30 years (aHR = 2.4; 95% CI 1.4,4.0), having >10 partners (aHR = 2.4; 95% CI 1.7,3.3), having a known HIV-positive male sex partner (aHR = 1.6; 95% CI 1.2, 2.0), unprotected anal intercourse with HIV positive/unknown male partners (aHR = 1.7; 95% CI 1.3, 2.3), and amphetamine (aHR = 1.6; 95% CI 1.1, 2.1) and popper (aHR = 1.7; 95% CI 1.3, 2.2) use.ConclusionsHIV seroincidence was high among MSM despite repeated HIV counseling and reported declines in sexual risk behaviors. Continuing development of new HIV prevention strategies and intensification of existing efforts will be necessary to reduce the rate of new HIV infections, especially among young men.