Validation of the Limiting Antigen Avidity Assay to Estimate Level and Trends in HIV Incidence in an A/D Epidemic in Rakai, Uganda.
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SUBMITTER: Laeyendecker O
PROVIDER: S-EPMC6461304 | biostudies-literature | 2019 Apr
REPOSITORIES: biostudies-literature
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Validation of the Limiting Antigen Avidity Assay to Estimate Level and Trends in HIV Incidence in an A/D Epidemic in Rakai, Uganda.
Laeyendecker Oliver O Gray Ronald H RH Grabowski M Kate MK Reynolds Steven J SJ Ndyanabo Anthony A Ssekasanvu Joseph J Fernandez Reinaldo E RE Wawer Maria J MJ Serwadda David D Quinn Thomas C TC
AIDS research and human retroviruses 20190129 4
The limiting-antigen avidity (LAg-Avidity) assay with viral load (VL) >1,000 copies/mL is being used to estimate population-level HIV incidence in Africa. However, this has not been validated in East Africa where HIV-1 subtypes A and D circulate. Sera from persons seen in two surveys (2008-2009 and 2012-2013) limited to those who attended the previous round of the Rakai Community Cohort in Uganda were analyzed. The performance of the current LAg-Avidity protocol, with a mean duration of recent i ...[more]
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Project description:Several laboratory assays on cross-sectional specimens for detecting recent HIV infections were developed, but these assays could not be applied in resource-limited and high HIV-incidence areas. This study describes the development of a rapid assay that can simultaneously detect the presence of HIV-1 antibodies of current and/or recent infection. The dot immuno-gold filtration assay (DIGFA) was used to detect recent infection on the principle of antibody avidity changes between recent and long-term infections. The dot immuno-gold silver staining filtration assay (DIGSSA) increases the sensitivity and accuracy of antibody detection by adding a silver staining step to the DIGFA. In the meantime the digital results were produced by the scanner for ambiguous specimens. Further, HIV-1 routine diagnostic antibody was detected simultaneously for improving practicability. The performance of the assays was then assessed through five serum panels with known serological statuses and seroconversion dates. The proportion of false recent infection (PFR) of the DIGSSA was obtained. Through the optimization of basic parameters for DIGSSA, six specimens were all classified correctly. DIGSSA demonstrated good repeatability and high sensitivity. The agreement of DIGSSA with the BED assay was 92.10% (? = 0.65) and 95.36% with the LAg-Avidity assay (? = 0.75). Moreover, the gray values of DIGSSA correlated well with BED ODn (R2 = 0.9397) and LAg-Avidity ODn (R2 = 0.9549). The PFR of DIGSSA was 2.73%, which was lower than that of the BED assay but higher than that of the LAg-Avidity assay. The DIGSSA can feasibly be applied to detect HIV infection and estimate HIV incidence.
| S-EPMC4981313 | biostudies-literature
Project description:Laboratory assays for identifying recent HIV-1 infections are widely used for estimating incidence in cross-sectional population-level surveys in global HIV-1surveillance. Adequate assay and laboratory performance are required to ensure accurate incidence estimates. The NIAID-supported External Quality Assurance Program Oversight Laboratory (EQAPOL) established a proficiency testing program for the most widely-used incidence assay, the HIV-1 Limiting Antigen Avidity EIA (LAg), with US Centers for Disease Control and Prevention (CDC)-approved kits manufactured by Sedia Biosciences Corporation and Maxim Biomedical. The objective of this program is to monitor the performance of participating laboratories. Four rounds of blinded external proficiency (EP) panels were distributed to up to twenty testing sites (7 North American, 5 African, 4 Asian, 2 South American and 2 European). These panels consisted of ten plasma samples: three blinded well-characterized HIV-1-seropositive samples that were included as replicates and an HIV-negative control. The seropositive samples spanned the dynamic range of the assay and are categorized as either recent or long-term infection. Participating sites performed the assay according to manufacturers' instructions and completed an online survey to gather information on kit manufacturer, lot of kit used, laboratory procedures and the experience of technicians. On average, fifteen sites participated in each round of testing, with an average of four sites testing with only the Maxim assay, seven testing with only the Sedia assay and five sites utilizing both assays. Overall, the Sedia and Maxim assays yielded similar infection status categorization across the laboratories; however, for most of the nine HIV+ samples tested, there were significant differences in the optical density readouts, ODn (N = 8) and OD (N = 7), between LAg kit manufacturers (p < 0.05 based on mixed effects models. The EQAPOL LAg program is important for monitoring laboratory performance as well as detecting variations between manufacturers of HIV-1incidence assays.
| S-EPMC6746377 | biostudies-literature
Project description:IntroductionHIV incidence estimates are important to characterize the status of an epidemic, identify locations and populations at high risk and to guide and evaluate HIV prevention interventions. We used the limiting antigen avidity assay (LAg) as part of a recent infection testing algorithm to estimate HIV incidence in the Akwa Ibom AIDS Indicator Survey (AKAIS), Nigeria.MethodsIn 2017, AKAIS, a cross-sectional population-based study was conducted at the household (HH) level in 31 local government areas (LGAs) of Akwa Ibom state. Of the 8963 participants aged ≥15 years who were administered questionnaires for demographic and behavioural data, 8306 consented to HIV rapid testing. Whole-blood specimens were collected from 394 preliminary HIV-seropositive individuals for CD4+ cell count determination and plasma storage. Samples were shipped to a central quality laboratory for HIV confirmatory testing and viral load determination. A total of 370 HIV-positive specimens were tested for the recent HIV infection using the LAg assay.ResultsOf the 8306 consenting adults, the HIV prevalence was 4.8%. Of the 370 HIV-positive samples tested for HIV recency, the median age was 35 years, 48.8% had CD4+ cell count >500/mm3 and 81.3% was not virally suppressed. Viral suppression was greater among females (21%) than for males (13%). A total of 11 specimens were classified as recent based on the LAg assay and HIV viral load ≥1000 copies/mL. The weighted, adjusted HIV-1 incidence was 0.41/100 person-years (95% CI 0.16 to 0.66); translating to 13,000 new cases of HIV infections annually in Akwa Ibom, a state with a population of 5.5 million. The HIV incidence rate was similar in females and males (0.41% and 0.42% respectively). The incidence rate was the highest among participants aged 15 to 49 years (0.44%, 95% CI 0.15 to 0.74) translating to 11,000 new infections annually, about 85% of all new infections in the state.ConclusionsThe finding of the high HIV incidence among the 15 to 49-year age group calls for renewed and innovative efforts to prevent HIV infection among young adults in Akwa Ibom state.
| S-EPMC7900440 | biostudies-literature
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Project description:INTRODUCTION:Male circumcision (MC) is an effective intervention to reduce HIV acquisition in men in Africa. We conducted a cost analysis using longitudinal data on expenditures on services and community mobilization to estimate the marginal cost of MC over time and understand cost drivers during scale-up. METHODS:We used a time series with monthly records from 2008 to 2013, for a total of 72 monthly observations, from the Rakai MC Program in Uganda. Generalized linear models were used to estimate the marginal cost of an MC procedure. RESULTS:The marginal cost per MC in a mobile camp was $23 (P < 0.01) and in static facilities was $35 (P < 0.1). Major cost drivers included supplies in mobile camps with increasing numbers of surgeries, savings due to task shifting from physicians to clinical officers, and increased efficiency as personnel became more experienced. CONCLUSIONS:As scale-up continues, marginal costs may increase because of mobilization needed for less motivated late adopters, but improved efficiency could contain costs.
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Project description:Background & aimsAccurate HCV incidence estimates are critical for monitoring progress towards HCV elimination goals, including an 80% reduction in HCV incidence by 2030. Moreover, incidence estimates can help guide prevention and treatment programming, particularly in the context of the US opioid epidemic.MethodsAn inexpensive, Genedia-based HCV IgG antibody avidity assay was evaluated as a platform to estimate cross-sectional, population-level primary HCV incidence using 1,840 HCV antibody and RNA-positive samples from 875 individuals enrolled in 5 cohort studies in the US and India. Using samples collected <2 years following HCV seroconversion, the mean duration of recent infection (MDRI) was calculated by fitting a maximum likelihood binomial regression model to the probability of appearing recent. Among samples collected ≥2 years post-HCV seroconversion, an individual-level false recent ratio (FRR) was calculated by estimating the probability of appearing recent using an exact binomial test. Factors associated with falsely appearing recent among samples collected ≥2 years post seroconversion were determined by Poisson regression with generalized estimating equations and robust variance estimators.ResultsAn avidity index cut-off of <40% resulted in an MDRI of 113 days (95% CI 84-146), and FRRs of 0.4% (95% CI 0.0-1.2), 4.6% (95% CI 2.2-8.3), and 9.5% (95% CI 3.6-19.6) among individuals who were HIV-uninfected, HIV-infected, and HIV-infected with a CD4 count <200/μl, respectively. No variation was seen between HCV genotypes 1 and 3. In hypothetical scenarios of high-risk settings, a sample size of <1,000 individuals could reliably estimate primary HCV incidence.ConclusionsThis cross-sectional approach can estimate primary HCV incidence for the most common genotypes. This tool can serve as a valuable resource for program and policy planners seeking to monitor and reduce HCV burden.Lay summaryDetermining the rate of new hepatitis C virus (HCV) infections in a population is critical to monitoring progress toward HCV elimination and to appropriately guide control efforts. However, since HCV infections are most often initially asymptomatic, it is difficult to estimate the rate of new HCV infections without following HCV-uninfected people over time and repeatedly testing them for HCV infection. Here, we present a novel, resource-efficient method to estimate the rate of new HCV infections in a population using data from a single timepoint.
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Project description:BackgroundHuman immunodeficiency virus (HIV) superinfection has been documented in high-risk individuals; however, the rate of superinfection among HIV-infected individuals within a general population remains unknown.MethodsA novel next-generation ultra-deep sequencing technique was utilized to determine the rate of HIV superinfection in a heterosexual population by examining two regions of the viral genome in longitudinal samples from recent HIV seroconverters (n=149) in Rakai District, Uganda.ResultsThe rate of superinfection was 1.44 per 100 person years (PYs) (95% confidence interval [CI], .4-2.5) and consisted of both inter- and intrasubtype superinfections. This was compared to primary HIV incidence in 20 220 initially HIV-negative individuals in the general population in Rakai (1.15 per 100 PYs; 95% CI, 1.1-1.2; P= .26). Propensity score matching (PS) was used to control for differences in sociodemographic and behavioral characteristics between the HIV-positive individuals at risk for superinfection and the HIV-negative population at baseline and follow-up. After PS matching, the estimated rate of primary incidence was 3.28 per 100 PYs (95% CI, 2.0-5.3; P = .07) controlling for baseline differences and 2.51 per 100 PYs (95% CI, 1.5-4.3; P = .24) controlling for follow-up differences.ConclusionsThis suggests that the rate of HIV superinfection in a general population is substantial, which could have a significant impact on future public health and HIV vaccine strategies.
| S-EPMC3415936 | biostudies-literature
Project description:Understanding the extent to which HIV burden differs across communities and the drivers of local disparities is crucial for an effective and targeted HIV response. We assessed community-level variations in HIV prevalence, risk factors, and treatment and prevention service uptake in Rakai, Uganda.The Rakai Community Cohort Study (RCCS) is an open, population-based cohort of people aged 15-49 years in 40 communities. Participants are HIV tested and interviewed to obtain sociodemographic, behavioural, and health information. RCCS data from Aug 10, 2011, to May 30, 2013, were used to classify communities as agrarian (n=27), trading (n=9), or lakeside fishing sites (n=4). We mapped HIV prevalence with Bayesian methods, and characterised variability across and within community classifications. We also assessed differences in HIV risk factors and uptake of antiretroviral therapy and male circumcision between community types.17?119 individuals were included, 9215 (54%) of whom were female. 9931 participants resided in agrarian, 3318 in trading, and 3870 in fishing communities. Median HIV prevalence was higher in fishing communities (42%, range 38-43) than in trading (17%, 11-21) and agrarian communities (14%, 9-26). Antiretroviral therapy use was significantly lower in both men and women in fishing communities than in trading (age-adjusted prevalence risk ratio in men 0·64, 95% CI 0·44-0·97; women 0·53, 0·42-0·66) and agrarian communities (men 0·55, 0·42-0·72; women 0·65, 0·54-0·79), as was circumcision coverage among men (vs trading 0·48, 0·42-0·55; vs agrarian 0·64, 0·56-0·72). Self-reported risk behaviours were significantly higher in men than in women and in fishing communities than in other community types.Substantial heterogeneity in HIV prevalence, risk factors, and service uptake in Rakai, Uganda, emphasises the need for local surveillance and the design of targeted HIV responses. High HIV burden, risk behaviours, and low use of combination HIV prevention in fishing communities make these populations a priority for intervention.National Institute of Mental Health, the National Institute of Allergy and Infectious Diseases, the National Institute of Child Health and Development, and the National Institute for Allergy and Infectious Diseases Division of Intramural Research, National Institutes of Health; the Bill & Melinda Gates Foundation; and the Johns Hopkins University Center for AIDS Research.
| S-EPMC4973864 | biostudies-literature
Project description:ImportanceMedical male circumcision (MMC) and antiretroviral therapy (ART) are proven HIV prevention interventions, but there are limited data on the population-level effect of scale-up of these interventions in sub-Saharan Africa. Such evaluation is important for planning and resource allocation.ObjectiveTo examine whether increasing community MMC and ART coverage was associated with reduced community HIV incidence in Rakai District, Uganda.Design, setting, and participantsUsing person-level data from population-based surveys conducted from 1999 through 2013 in 45 rural Rakai communities, community-level ART and MMC coverage, sociodemographics, sexual behaviors, and HIV prevalence and incidence were estimated in 3 periods: prior to the availability of ART and MMC (1999-2004), during early availability of ART and MMC (2004-2007), and during mature program scale-up (2007-2013).ExposuresCommunity MMC coverage in males and ART coverage in HIV-positive persons of the opposite sex based on self-reported MMC status and ART use.Main outcomes and measuresAdjusted incidence rate ratios (IRRs) for sex-specific community HIV incidence estimated using multivariable Poisson regression with generalized estimating equations.ResultsFrom 1999 through 2013, 44,688 persons participated in 1 or more surveys (mean age at the first survey, 24.6 years [range, 15-49]; female, 56.5%; mean survey participation rate, 92.6% [95% CI, 92.4%-92.7%]). Median community MMC coverage increased from 19% to 39%, and median community ART coverage rose from 0% to 21% in males and from 0% to 26% in females. Median community HIV incidence declined from 1.25 to 0.84 per 100 person-years in males, and from 1.25 to 0.99 per 100 person-years in females. Among males, each 10% increase in community MMC coverage was associated with an adjusted IRR of 0.87 (95% CI, 0.82-0.93). Comparing communities with MMC coverage more than 40% (mean male community incidence, 1.03 per 100 person-years) with communities with coverage of 10% or less (mean male incidence, 1.69 per 100 person-years), the adjusted IRR was 0.61 (95% CI, 0.43-0.88). For each 10% increase in female self-reported ART coverage, there was no significant reduction in male HIV incidence (adjusted IRR, 0.95 [95% CI, 0.81-1.13]). Comparing communities with female ART coverage more than 20% (mean male incidence, 0.87 per 100 person-years) to communities with female ART coverage of 20% or less (mean male incidence, 1.17 per 100 person-years), the adjusted IRR was 0.77 (95% CI, 0.61-0.98). Neither MMC nor male ART coverage was associated with lower female community HIV incidence.Conclusions and relevanceIn Rakai, Uganda, increasing community MMC and female ART coverage was associated with lower community HIV incidence in males. If similar associations are found elsewhere, this would support further scale-up of MMC and ART for HIV prevention in sub-Saharan Africa.
| S-EPMC5027874 | biostudies-literature
Project description:HIV and malaria exert co-pathogenic effects. Malaria surveillance data are necessary for public health strategies to reduce the burden of disease in high HIV prevalence settings.This was a longitudinal cohort study to assess the burden of malaria in rural Rakai, Uganda. Households were visited monthly for 1 year to identify confirmed clinical malaria (CCM), or parasitaemia with temperature >37.5 °C, and asymptomatic parasitaemia (AP). Interviews of the adult or child's caregiver and clinical and laboratory assessments were conducted. Rapid diagnostic testing for malaria and anaemia was performed if participants were febrile and anti-malarial treatment given per Uganda Ministry of Health 2010 guidelines. Blood was drawn at every household visit to assess for parasitaemia, and blood smears were assessed at the Rakai Health Science Programme laboratory.A total of 1640 participants were enrolled, including 975 children aged 6 months up to 10 years, 393 adult caregivers, and 272 adolescent/adult household members from 393 randomly selected households in two representative communities. 1459 (89 %) participants completed all study visits. CCM was identified in 304 (19 %) participants, with the highest incidence rate for CCM of 0.38 per person-year (ppy) identified in children <5 years, and rates decreased with age; the rates were 0.27, 0.16, and 0.09 ppy for ages 5-<10 years, 10-<18 years, and adults 18+ years, respectively. AP was identified in 943 (57 %) participants; the incidence rate was 1.99 ppy for <5 years, 2.72 ppy for 5-<10 years, 2.55 ppy for 10-<18 years, and 0.86 ppy among adults, with 92 % of cases being attributed to Plasmodium falciparum by smear. 994 (61 %) individuals had at least one positive smear; 342 (21 %) had one positive result, 203 (12 %) had two, 115 (7 %) had three, and 334 (21 %) had >3 positive smears during follow-up. Seasonal rates generally followed the rains and peaked during July, then decreased through November before increasing again.Plasmodium falciparum infection remains high in rural Uganda. Increased malaria control interventions should be prioritized. Trial registration Clinicaltrials.gov identifier NCT01265407.
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