Publications by authors named "Andrew F Longosz"

Introduction: Incentives conditional on school attendance or on remaining free of sexually transmitted infections have produced mixed results in reducing HIV incidence.

Methods: HIV-negative adolescent girls and young women aged 15-22%-50% of whom were out of school-were recruited from 293 clusters in Eswatini from urban (30%) and rural areas (70%).Financial incentives conditional on education attendance were randomly allocated at the cluster level.

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Background: Eswatini continues to have the highest prevalence of HIV in the world, and one of the highest HIV incidences among adult populations (aged 15-49). This analysis reports on both key elements of study design/protocol and baseline results from an impact evaluation of an intervention incentivizing (i) initiation, enrolment, attendance or completion of some form of education, and (ii) lower risk sexual behaviour.

Methods: The impact evaluation employs a two by two factorial design in which participants are enrolled in either the incentive for education arm ('education treatment arm' providing a conditional cash incentive) or the control arm ('education control arm').

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HIV-1 undergoes multiple rounds of error-prone replication between transmission events, resulting in diverse viral populations within and among individuals. In addition, the virus experiences different selective pressures at multiple levels: during the course of infection, at transmission, and among individuals. Disentangling how these evolutionary forces shape the evolution of the virus at the population scale is important for understanding pathogenesis, how drug- and immune-escape variants are likely to spread in populations, and the development of preventive vaccines.

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Article Synopsis
  • - The report discusses a confirmed case of linked heterosexual HIV superinfection (HIV-SI) in a woman who developed a second strain of HIV from her husband while already having a chronic HIV infection.
  • - Researchers analyzed the woman’s and her husband’s serum neutralizing antibody (NAb) responses against various HIV strains before and after the superinfection occurred.
  • - The findings reveal that the woman had a strong NAb response against her original HIV strain but lacked effective NAb activity against the newly acquired superinfecting strain, suggesting that studying such cases can provide insights into natural protection against HIV.
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We analyzed the impact of HIV viral load on the performance of a limiting antigen avidity enzyme immunoassay (LAg-Avidity assay) and determined if this assay could be used to identify viral breakthrough. Three groups of samples were tested: (1) 18 individuals (30 samples) previously identified as elite suppressors; (2) 18 individuals (72 samples) who were continually suppressed on antiretroviral treatment (ART) with 1 sample before and 2-6 samples (one/year) after ART initiation; and (3) 20 individuals (179 samples) on ART who had evidence of viral breakthrough (>400 copies/ml) with subsequent viral suppression. Elite suppressors had the lowest LAg-Avidity assay values.

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Objective: This study examined HIV superinfection in HIV-infected women postpartum, and its association with mother-to-child transmission (MTCT).

Design: Plasma samples were obtained from HIV-infected women who transmitted HIV to their infants after 6 weeks of age (transmitters, n = 91) and HIV-infected women who did not transmit HIV to their infants (nontransmitters, n = 91). These women were originally enrolled in a randomized trial for prevention of MTCT of HIV in Malawi (Post-Exposure Prophylaxis of Infants trial in Malawi).

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The CAPRISA 004 preexposure prophylaxis (PrEP) randomized trial demonstrated that women who used a vaginal gel containing the antiretroviral drug tenofovir (TFV) had a 39% lower risk of acquiring human immunodeficiency virus (HIV). It is not known whether topical TFV alters the antibody response to breakthrough HIV infection. In this study, antibody maturation was evaluated using 3 serologic assays: the BED capture enzyme immunoassay (CEIA), the Bio-Plex (Luminex) assay, and the Bio-Rad avidity assay.

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We compared the serologic response to HIV infection in Ugandan women with HIV subtype A (N=82) and D (N=32) infection using a limiting antigen avidity assay (LAg-Avidity assay); 2,614 samples were analyzed. Study participants were followed a median of 6.6 years after HIV seroconversion.

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Background: Multi-assay algorithms (MAAs) can be used to estimate HIV incidence in cross-sectional surveys. We compared the performance of two MAAs that use HIV diversity as one of four biomarkers for analysis of HIV incidence.

Methods: Both MAAs included two serologic assays (LAg-Avidity assay and BioRad-Avidity assay), HIV viral load, and an HIV diversity assay.

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Introduction: Analysis of samples from Uganda using serologic HIV incidence assays reveal that individuals with subtype D infection often have weak humoral immune responses to HIV infection. It is unclear whether this reflects a poor initial response to infection or a waning antibody response later in infection.

Materials And Methods: Samples (N = 2614) were obtained from 114 women aged 18-45 years in the Ugandan Genital Shedding and Disease Progression Study cohort (2001-2009; 82 subtype A, 32 subtype D; median 23 samples/women, range 3-41 samples, median follow-up of 6.

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Objectives: To evaluate factors associated with misclassification by the limiting-antigen avidity (LAg-avidity) assay among individuals with long-standing HIV infection.

Design: Samples were obtained from the Multicenter AIDS Cohort Study and AIDS Linked to the IntraVenous Experience cohort (1089 samples from 667 individuals, 595 samples collected 2-4 years and 494 samples collected 4-8 years after HIV seroconversion). Paired samples from both time points were available for 422 (63.

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Background: A limiting antigen avidity enzyme immunoassay (HIV-1 LAg-Avidity assay) was recently developed for cross-sectional HIV incidence estimation. We evaluated the performance of the LAg-Avidity assay alone and in multi-assay algorithms (MAAs) that included other biomarkers.

Methods And Findings: Performance of testing algorithms was evaluated using 2,282 samples from individuals in the United States collected 1 month to >8 years after HIV seroconversion.

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Background: Accurate and reliable laboratory-based assays are needed for estimating HIV-1 incidence from cross-sectional samples. We recently described the development of a customized, HIV-1-specific Bio-Plex assay that allows for the measurement of HIV-specific antibody levels and avidity to multiple analytes for improved HIV-1 incidence estimates.

Methods: To assess intra- and inter-laboratory assay performance, prototype multiplex kits were developed and evaluated by three distinct laboratories.

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Previous studies demonstrated that individuals with subtype D HIV infection who had been infected for 2 or more years were frequently misclassified as assay positive using cross-sectional incidence assays. Samples from 510 subjects (212 subtype A, 298 subtype D) who were infected for 2.2 to 14.

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