CROI 2016 Abstract eBook

Abstract Listing

Poster Abstracts

518

Acute Retroviral Syndrome: Useful for Guiding Testing for Acute HIV Infection? Martin Hoenigl ; Nella Green; Sanjay R. Mehta; Martha Camacho; Sara Gianella; Davey M. Smith; Susan J. Little Univ of California San Diego, San Diego, CA, USA

Background: Diagnostic testing for HIV is often initiated with a 4 th generation immunoassay or an HIV rapid antibody test. While recent healthcare guidelines recommend 4 th generation HIV testing to detect acute HIV infection (AHI), the recommended p24 antigen based methods are limited by imperfect sensitivities for antibody negative AHI. Field- based testing programs generally rely on point-of-care rapid HIV antibody testing only, with specific AHI testing limited to persons presenting with signs and symptoms (S/Sx) consistent with an acute retroviral syndrome. However, the proportion of persons with AHI presenting symptomatic for their diagnostic test remains unknown. The objective of this study was to determine the proportion of persons with AHI presenting symptomatic for their diagnostic test. Methods: This is a prospective observational cohort study in persons diagnosed with AHI (defined as negative HIV antibody test in the presence of detectable HIV-1 RNA) who were enrolled in the San Diego Primary Infection Resource Consortium (SD PIRC) between June 2007 and December 2014. We analyzed S/Sx on or immediately prior to the day of HIV-1 nucleic acid testing (NAT; without pooling) in 90 individuals diagnosed with AHI in a community-based program, offering universal (i.e. independent of S/Sx) AHI screening in San Diego, California. Results: Forty-seven (52%) of the 90 persons identified with AHI reported ongoing S/Sx (median 6, IQR 4-8) at the time of HIV-1 RNA screening. Another 25 (28%) reported S/ Sx that had occurred during the 14 days prior that had resolved by the time of the first positive NAT test and 12 (13%) reported S/Sx that started after the test, while only 6 (7%) reported no S/Sx. Viral loads were significantly higher (p=0.001) and CD4/CD8 ratios lower (p=0.047) in those 72 individuals reporting S/Sx before or at the time of NAT screening compared to those 18 that did not have S/Sx prior to HIV-1 NAT screening (Table). Conclusions: HIV diagnostic testing strategies that limit AHI testing to those presenting with S/Sx fail to identify about half of persons with AHI. In contrast, HIV-1 NAT provided to persons with S/Sx during the two weeks before the test may identify 80% of AHI cases. Such an approach may help maximizing the yield of AHI diagnoses in field-based testing programs, where universal 4 th -generation testing frequently is not available.

Poster Abstracts

519

Comparative Sensitivity of 8 HIV Rapid Tests in HIV-Positive Patients Heinrich Scheiblauer 1 ; Siri Göpel 2 ;TanjaWestenberger 1 ; Christoph Stephan 2 1 Paul-Ehrlich-Inst, Langen, Germany; 2 Goethe Univ Hosp Frankfurt, Frankfurt, Germany

Background: HIV rapid test devices (HIV-RTD) often show a wide range of performances due to different HIV assay generations, test technologies and specimen types. Methods: Test sensitivity of eight HIV-RTDs including assay generations 2nd (IgG sensitive), 3rd (IgG/IgM sensitive) and 4th (Antigen/Antibody) assays and different test formats was evaluated head-to-head in a cross-sectional study with 206 confirmed HIV positive patients paired for serum/plasma, whole blood and oral fluid, and in 10 seroconversion panels (105 serial samples). Comparison included laboratory-based HIV screening and confirmation tests established in the EU. Results: The sensitivity of HIV-RTDs in patients was 98.1%-99.5%with serum/plasma, 97.1%-99.5%with whole blood and 92.7%with oral fluid. False-negative results with serum/plasma were from recent infection. With whole blood, two HIV-RTDs were less sensitive in recent infection than with serum and one HIV RTD was false negative also in chronic infection. With oral fluid there were 15 false-negative results from recent and chronic infection. 4th generation HIV-RTD was not superior to 3rd generation HIV RTDs in patients. The window periods of the HIV-RTDs relative to HIV-RNA in the seroconversion panels ranged from 9.9 to 18.9 days, and correlated with the order of sensitivity of the tests on the HIV patients. The figure illustrates the findings on time to detection of HIV infection, compared to HIV-RNA (window period) for the HIV rapid tests and the laboratory-based HIV assays (mean values).

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CROI 2016