Last data update: Sep 23, 2024. (Total: 47723 publications since 2009)
Records 1-4 (of 4 Records) |
Query Trace: McDougal JS [original query] |
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Controlling HIV epidemics among injection drug users: eight years of cross-border HIV prevention interventions in Vietnam and China
Hammett TM , Des Jarlais DC , Kling R , Kieu BT , McNicholl JM , Wasinrapee P , McDougal JS , Liu W , Chen Y , Meng D , Doan N , Huu Nguyen T , Ngoc Hoang Q , Van Hoang T . PLoS One 2012 7 (8) e43141 INTRODUCTION: HIV in Vietnam and Southern China is driven by injection drug use. We have implemented HIV prevention interventions for IDUs since 2002-2003 in Lang Son and Ha Giang Provinces, Vietnam and Ning Ming County (Guangxi), China. METHODS: Interventions provide peer education and needle/syringe distribution. Evaluation employed serial cross-sectional surveys of IDUs 26 waves from 2002 to 2011, including interviews and HIV testing. Outcomes were HIV risk behaviors, HIV prevalence and incidence. HIV incidence estimation used two methods: 1) among new injectors from prevalence data; and 2) a capture enzyme immunoassay (BED testing) on all HIV+ samples. RESULTS: We found significant declines in drug-related risk behaviors and sharp reductions in HIV prevalence among IDUs (Lang Son from 46% to 23% [p<0.001], Ning Ming: from 17% to 11% [p = 0.003], and Ha Giang: from 51% to 18% [p<0.001]), reductions not experienced in other provinces without such interventions. There were significant declines in HIV incidence to low levels among new injectors through 36-48 months, then some rebound, particularly in Ning Ming, but BED-based estimates revealed significant reductions in incidence through 96 months. DISCUSSION: This is one of the longest studies of HIV prevention among IDUs in Asia. The rebound in incidence among new injectors may reflect sexual transmission. BED-based estimates may overstate incidence (because of false-recent results in patients with long-term infection or on ARV treatment) but adjustment for false-recent results and survey responses on duration of infection generally confirm BED-based incidence trends. Combined trends from the two estimation methods show sharp declines in incidence to low levels. The significant downward trends in all primary outcome measures indicate that the Cross-Border interventions played an important role in bringing HIV epidemics among IDUs under control. The Cross-Border project offers a model of HIV prevention for IDUs that should be considered for large-scale replication. |
Assessment of BED HIV-1 incidence assay in seroconverter cohorts: effect of individuals with long-term infection and importance of stable incidence
McNicholl JM , McDougal JS , Wasinrapee P , Branson BM , Martin M , Tappero JW , Mock PA , Green TA , Hu DJ , Parekh B . PLoS One 2011 6 (3) e14748 BACKGROUND: Performance of the BED assay in estimating HIV-1 incidence has previously been evaluated by using longitudinal specimens from persons with incident HIV infections, but questions remain about its accuracy. We sought to assess its performance in three longitudinal cohorts from Thailand where HIV-1 CRF01_AE and subtype B' dominate the epidemic. DESIGN: BED testing was conducted in two longitudinal cohorts with only incident infections (a military conscript cohort and an injection drug user cohort) and in one longitudinal cohort (an HIV-1 vaccine efficacy trial cohort) that also included long-term infections. METHODS: Incidence estimates were generated conventionally (based on the number of annual serocoversions) and by using BED test results in the three cohorts. Adjusted incidence was calculated where appropriate. RESULTS: For each longitudinal cohort the BED incidence estimates and the conventional incidence estimates were similar when only newly infected persons were tested, whether infected with CRF01_AE or subtype B'. When the analysis included persons with long-term infections (to mimic a true cross-sectional cohort), BED incidence estimates were higher, although not significantly, than the conventional incidence estimates. After adjustment, the BED incidence estimates were closer to the conventional incidence estimates. When the conventional incidence varied over time, as in the early phase of the injection drug user cohort, the difference between the two estimates increased, but not significantly. CONCLUSIONS: Evaluation of the performance of incidence assays requires the inclusion of a substantial number of cohort-derived specimens from individuals with long-term HIV infection and, ideally, the use of cohorts in which incidence remained stable. Appropriate adjustments of the BED incidence estimates generate estimates similar to those generated conventionally. |
Determination of mean recency period for estimation of HIV type 1 incidence with the BED-capture EIA in persons infected with diverse subtypes
Parekh BS , Hanson DL , Hargrove J , Branson B , Green T , Dobbs T , Constantine N , Overbaugh J , McDougal JS . AIDS Res Hum Retroviruses 2010 27 (3) 265-73 The IgG capture BED enzyme immunoassay (BED-CEIA) was developed to detect recent HIV-1 infection for the estimation of HIV-1 incidence from cross-sectional specimens. The mean time interval between seroconversion and reaching a specified assay cutoff value [referred to here as the mean recency period (omega)], an important parameter for incidence estimation, is determined for some HIV-1 subtypes, but testing in more cohorts and new statistical methods suggest the need for a revised estimation of omega in different subtypes. A total of 2927 longitudinal specimens from 756 persons with incident HIV infections who had been enrolled in 17 cohort studies was tested by the BED-CEIA. The omega was determined using two statistical approaches: (1) linear mixed effects regression (omega(1)) and (2) a nonparametric survival method (omega(2)). Recency periods varied among individuals and by population. At an OD-n cutoff of 0.8, omega(1) was 176 days (95% CL 164-188 days) whereas omega(2) was 162 days (95% CL 152-172 days) when using a comparable subset of specimens (13 cohorts). When method 2 was applied to all available data (17 cohorts), omega(2) ranged from 127 days (Thai AE) to 236 days (subtypes AG, AD) with an overall omega(2) of 197 days (95% CL 173-220). About 70% of individuals reached a threshold OD-n of 0.8 by 197 days (mean omega) and 95% of people reached 0.8 OD-n by 480 days. The determination of omega with more data and new methodology suggests that omega of the BED-CEIA varies between different subtypes and/or populations. These estimates for omega may affect incidence estimates in various studies. |
Evaluating the BED capture enzyme immunoassay to estimate HIV incidence among adults in three countries in Sub-Saharan Africa
Kim AA , McDougal JS , Hargrove J , Rehle T , Pillay-Van Wyk V , Puren A , Ekra A , Borget-Alloue MY , Adje-Toure C , Abdullahi AS , Odawo L , Marum L , Parekh BS . AIDS Res Hum Retroviruses 2010 26 (10) 1051-61 Serological assays for estimating HIV-1 incidence are prone to misclassification, limiting the accuracy of the incidence estimate. Adjustment factors have been developed and recommended for estimating assay-based HIV-1 incidence in cross-sectional settings. We evaluated the performance of the recommended adjustment factors for estimating incidence in national HIV surveys in three countries in sub-Saharan Africa. The BED-capture enzyme immunoassay was applied to stored blood specimens from (1) pregnant women aged 15-49 years attending antenatal clinics in Cote d'Ivoire (1998-2004), (2) adults aged 15-49 years participating in a demographic health survey in Kenya (2003), and (3) adults aged 15-49 years participating in a national household serosurvey in South Africa (2005). Assay-derived incidence estimates were corrected for misclassification using recommended adjustment factors and, where possible, were compared to mathematically modeled incidence in the same populations. Trends in HIV prevalence were compared to trends in assay-derived incidence to assess plausibility in the assay-derived trends. Unadjusted incidence was 3.8% [95% confidence interval (CI) 3.3-4.5] in Cote d'Ivoire, 3.5% (2.7-4.3) in Kenya, and 4.4% (CI 2.3-6.5]) in South Africa. Adjusted incidence was 2.9% (CI 2.1-3.7) in Cote d'Ivoire, 2.6% (CI 2.0-3.2) in Kenya, and 2.4% (CI 1.7-3.1) in South Africa. After adjustment, peak incidence shifted from older to younger age groups in Cote d'Ivoire and South Africa. Modeled HIV incidence was 1.0% (CI 1.02-1.08) in Kenya and 2.0% (CI 1.7-2.4) in South Africa. After applying the recommended adjustments factors, adjusted assay-derived estimates remained implausibly high in two of three populations evaluated. For more accurate measures of assay-derived population incidence, adjustment factors must be locally derived and validated. Until improved assays are available, caution should be applied in the use and interpretation of data from incidence assays. |
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