CROI 2015 Program and Abstracts

Abstract Listing

Poster Abstracts

Conclusions: Our generalized entropy measure of viral diversity demonstrates the potential for improving accuracy when identifying recent HIV-1 infections. We also show that to properly compare and evaluate assay performances, the distribution of time-since-infection in the validation dataset needs to be accounted for. 613 Acute Infections, Cost and Time to Reporting of HIV Test Results in US State Public Health Laboratories MuazzamNasrullah 1 ; Laura G.Wesolowski 1 ; Steven F. Ethridge 1 ; Kevin Cranston 2 ; Robert A. Myers 3 ; JamesT. Rudrik 4 ; Angela B. Hutchinson 1 ; Barbara G.Werner 2 1 US Centers for Disease Control and Prevention (CDC), Atlanta, GA, US; 2 Massachusetts Department of Public Health, Boston, MA, US; 3 Maryland Department of Health and Mental Hygiene, Baltimore, MD, US; 4 Michigan Department of Community Health, Lansing, MI, US Background: In 2014, CDC recommended an HIV diagnostic algorithm (repeatedly reactive [RR] 4th-generation immunoassay [IA] that detects HIV-1 antigen and HIV antibody, followed by an HIV-1/HIV-2 differentiation antibody IA, and when negative or indeterminate, an HIV-1 nucleic acid test [NAT]) to detect acute infections and to reduce misclassification of HIV-2 as HIV-1 infections. In three U.S. state public health laboratories (PHLs), we characterized the yield of acute infections, time to reporting of acute and antibody-positive HIV-1 infections, and cost per positive specimen. Methods: Routine HIV testing data were collected from 7/1/2012- 6/30/2013 for Massachusetts (MA) and Maryland (MD) PHLs, and from 11/27/12- 6/30/2013 for Michigan (MI) PHL. MA and MI used the CDC algorithmwith NAT conducted by a referral laboratory, and MD used a modified algorithm. In MD PHL, 4th-generation IA RR specimens were followed by Western Blot (WB), and those with negative or indeterminate WB results were tested with an HIV-1/HIV-2 differentiation IA and an HIV-1 NAT, and if positive by NAT, confirmed by a different HIV-1 NAT. HIV-2 positive specimens on an HIV-1/HIV-2 differentiation IA were tested with HIV-2 WB and differential HIV-1/HIV-2 proviral DNA polymerase chain reaction (PCR). In each PHL, we determined the time from specimen receipt to laboratory reporting of test results, and total testing and labor costs per HIV positive (HIV-1 and HIV-2). Results: Among 7,914 specimens fromMA PHL, 6,069 fromMI PHL and 36,266 fromMD PHL, 8, 1 and 19 acute infections were identified, respectively (Table). For MA and MD PHL, 1 specimen each was identified as HIV-2 positive. The median time from specimen receipt to laboratory reporting of test results for acute infections was 7, 11 and 7 days and for HIV-1 antibody-confirmed infections was 3, 2 and 3 days, respectively. The cost per HIV positive specimen was $336 in MA PHL, $281 in MI PHL and $221 in MD PHL.

Poster Abstracts

Conclusions: Fourth-generation IA, coupled with antibody tests and NAT, detected acute infections in PHLs that may have been missed if an antibody-only test such as the Western Blot had been used as a confirmatory test. Promotion of the CDC HIV testing algorithm, with quicker reporting of acute infections, will facilitate public health intervention to interrupt transmission. 614 The POC Alere q HIV-1/2 Detect Test for Detection and Quantification of HIV-2 Ming Chang 1 ; KatjaWeimar 2 ; Dana N. Raugi 1 ; Robert A. Smith 1 ; Selly Ba 3 ; Moussa Seydi 3 ; Katrin Steinmetzer 2 ; RobertW. Coombs 1 ; Geoffrey S. Gottlieb 1 UW-Dakar HIV-2 Study Group 1 University of Washington, Seattle, WA, US; 2 Alere Technologies GmbH, Jena, Germany; 3 Service des Maladies Infectieuses, CHNU de Fann, Dakar, Senegal Background: Rapid point-of-care (POC) nucleic acid testing (NAT) that can detect, differentiate and quantify HIV-1 and HIV-2 RNA/DNA has the potential to improve the cascade of care and antiretroviral therapy monitoring. In addition, the new 4 th -generation CDC algorithm for HIV diagnostic testing specifies differential HIV-1 and HIV-2 serologic and nucleic acid testing, but there are no FDA-approved confirmatory HIV-2 NAT assays currently available. Methods: We compared the ability of the Alere q HIV-1/2 Detect test with 25 m L of sample input and the recently-validated University of Washington (UW)-Abbott m2000 HIV-2 viral load assay to detect and differentiate between HIV-1 and HIV-2. Under a “research use only” protocol, the Alere q HIV-1/2 platformwas used to quantify HIV-2 plasma RNA viral load. Clinical samples from HIV-2 and HIV-1/2 dually-infected patients from Senegal were tested, along with the WHO HIV-2 international standard and HIV-2 reference strains. All testing was performed in the CLIA-certified UW Clinical Retrovirology Lab. Results: The Alere HIV-1/2 Detect test correctly differentiated HIV-1 from HIV-2 in 100% of 77 patient samples tested (N=17 HIV-1, 60 HIV-2) and detected HIV-2 nucleic acids in 56 of 118 (47%) plasma samples from HIV-2–infected individuals. The Alere test detected HIV-2 in group A and group B specimens, as well as the WHO international standard (HIV-2 CAM2 ; group A) and other reference isolates. The overall concordance between the Alere test and the Abbott m2000 assay was 56/82 (68%) detected; concordance improved to 44/48 (92%) for samples with HIV-2 viral loads >50 RNA copies/mL. The Alere q HIV-1/2 RUO viral load test had a lower limit of detection of HIV-2 RNA in plasma of ~50 copies/ml (input volume=25 m L; HIV-2 ROD standards calibrated on the UWm2000 assay) . The Alere test was able to quantify HIV-2 plasma viral load with good linearity for both HIV-2 groups A and B in samples from 50 to 500,000 copies/ml (R 2 >0.99).

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CROI 2015