CROI 2015 Program and Abstracts

Abstract Listing

Poster Abstracts

673 Development and Comparison of Hepatitis C Cross-Sectional Incidence Testing Methods Eshan U. Patel 1 ; Andrea Cox 2 ; Shruti H. Mehta 3 ; Caroline E. Mullis 2 ; Jeffrey Quinn 2 ; Gregory D. Kirk 3 ;Thomas C. Quinn 1 ; Oliver B. Laeyendecker 1 1 National Institute of Allergy and Infectious Diseases (NIAID), Baltimore, MD, US; 2 Johns Hopkins University School of Medicine, Baltimore, MD, US; 3 Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, US Background: The traditional method to determine hepatitis C (HCV) incidence requires longitudinal cohorts. However, cohort studies are challenging because they are expensive, time consuming, and may not achieve sufficient follow-up in high-risk populations such as people who inject drugs (PWIDs). The ability to detect recently infected individuals from a cross-sectional survey would reduce the need for longitudinal data. We present two HCV avidity-based tests for recent infection and compare testing algorithms to identify newly infected individuals. Methods: Samples with previously determined HCV RNA levels from 72 PWIDs (396 samples) with known dates of infection from the Baltimore Before-and-After Acute Study of Hepatitis (BBAASH) cohort and 1,087 PWIDs (1,471 samples) infected for ≥ 2 years from the AIDS Linked to the Intravenous Experience (ALIVE) cohort were tested for HCV avidity by two assays: (1) the Ortho HCV 3.0 ELISA, treated with 0.25M diethylamine and (2) the Genedia HCV 3.0 ELISA, treated with 11M urea. The avidity index was the optical density ratio between treated and untreated wells. High precision of cross-sectional incidence estimation is characterized by a large mean duration of recent infection (MDRI), the average length of time that people with newly acquired infection are classified as recent, and a small false-recent rate (FRR), the proportion of non-recent infections misclassified as being recent. These properties were evaluated for 28 testing algorithms that included the two avidity assays alone at various cutoffs with and without viral load testing. Results: At various avidity index cutoffs, the MDRI varied between 234.5–392.8 days for the Ortho 3.0 avidity assay alone and 74.5–354.0 days for the Genedia 3.0 avidity assay alone. Both avidity assays produced high FRRs, primarily due to individuals who spontaneously cleared the virus. The FRRs for the avidity assays decreased when evaluated in combination with HCV RNA confirmation, but remained above the ideal FRR of 0% (Table 1).

Conclusions: The HCV avidity and viral load testing algorithms were able to identify recently infected individuals. However, further work is needed to determine additional biomarkers that will reduce the FRRs of these testing algorithms. Efforts to optimize cross-sectional HCV incidence testing will contribute to a more practical and timely method to determine rates of new infection, yielding more rapid assessment of the epidemic and of the impact of intervention efforts. 674 Risk Factors for Transmission of HCV Among HIV-Infected MSM: A Case-Control Study Joost W. Vanhommerig 1 ; Femke A. Lambers 1 ; Janke Schinkel 2 ; Joop E. Arends 3 ; Fanny N. Lauw 4 ; Kees Brinkman 5 ; Luuk Gras 6 ; Bart J. Rijnders 7 ; JanT. van der Meer 2 ; Maria Prins 1 1 GGD Amsterdam, Amsterdam, Netherlands; 2 Academic Medical Center, Amsterdam, Netherlands; 3 University Medical Center Utrecht, Utrecht, Netherlands; 4 Slotervaart Hospital, Amsterdam, Netherlands; 5 OLVG Hospital, Amsterdam, Netherlands; 6 Dutch HIV Monitoring Foundation, Amsterdam, Netherlands; 7 Erasmus University Medical Center, Rotterdam, Netherlands; 8 Academic Medical Center, Amsterdam, Netherlands Background: Since 2000, incidence of sexually acquired hepatitis C virus (HCV) infection has increased among HIV infected men who have sex with men (MSM). Only a few case- control and cohort studies evaluating transmission risk factors were conducted, and most of these studies initially were not designed to study HCV, but HIV-related behavior and characteristics. The MOSAIC study provides a unique opportunity to study risk factors for acute HCV infection in HIV-infected MSM. Methods: From 2009 onwards, HIV-infected MSMwith an acute HCV infection (cases) were prospectively included and followed at five hospitals in the Netherlands. For each case, one to two unmatched controls were recruited from the population of HIV-infected MSM without HCV. Written questionnaires were administered, covering socio-demographics, blood-borne risk factors for HCV infection, sexual risk behavior, and drug use. Clinical data on HIV-and HCV were acquired through linkage with databases from the Dutch HIV Monitoring Foundation. Determinants of HCV infection were analyzed using logistic regression. Results: Among 213 MSM (82 MSM with and 131 MSM without HCV infection), median age was 45.7 years (IQR:41.0-52.2). Ulcerative STI (OR:5.26,95%CI:1.72-16.1), receptive unprotected anal intercourse (rUAI;OR:5.05,95%CI:1.63-15.6), sharing sex toys (OR:3.98,95%CI:1.12-14.2), sharing straws when snorting drugs (OR:3.46,95%CI:1.41-8.47), unprotected fisting (OR:2.54,95%CI:1.01-6.42), and CD4 cell count at the last HCV negative visit prior to study entry (OR:1.74 per cube root lower, 95%CI:1.18-2.56) were independently associated with HCV acquisition. Of interest, injecting drug use was reported by only 12 men, and was not significantly associated in multivariable analysis; nor were anal rinsing, rectal bleeding, number of sex partners, meeting location, and group sex participation. No interactions were found. Conclusions: To our knowledge, this is the largest case-control study focusing on transmission of HCV among HIV-infected MSM. Besides known risk factors for HCV (rUAI, STI, fisting, and sharing of sex toys), associations between the sharing of straws when snorting drugs, and lower CD4 cell count and HCV acquisition were found. Our study confirms sexual transmission and a role of non-injecting drug use as a risk factor for HCV transmission. Further studies are needed on the role of CD4 cell count, as it is still unclear whether a lower CD4 cell count facilitates HCV infection or is a result of acute HCV infection itself (or both). 675 Behavioural and Treatment Interventions to Reduce HCV Transmissions in HIV+MSM Luisa Salazar-Vizcaya 1 ; Roger Kouyos 2 ; Cindy Zahnd 1 ; Manuel Battegay 3 ; Katharine Darling 4 ; Alexandra Calmy 5 ; Pietro L.Vernazza 6 ; Olivia Keiser 1 ; Andri Rauch 7 On behalf of the Swiss HIV Cohort Study 1 University of Bern, Bern, Switzerland; 2 University Hospital Zurich, Zürich, Switzerland; 3 University Hospital Basel, Basel, Switzerland; 4 Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland; 5 Geneva University Hospitals, Geneva, Switzerland; 6 Kantonsspital St Gallen, St Gallen, Switzerland; 7 University Hospital Bern, Inselspital, Bern, Switzerland Background: The incidence of hepatitis C virus (HCV) infections among HIV-infected men who have sex with men (MSM) increased markedly in industrialized countries and is associated with high risk sexual behaviour including traumatic sex. Finding the most effective interventions to control this epidemic is key to reducing liver-related morbidity and mortality in these patients. HCV treatments with direct-acting antivirals (DAAs) achieve high cure rates, but the role of these therapies on reducing HCV transmission remains uncertain. Methods: Based on behavioural, epidemiological and clinical information collected prospectively in the Swiss HIV Cohort Study (SHCS), we developed a deterministic mathematical model for sexually transmitted HCV infections among HIV-positive MSM in Switzerland. We reproduced the epidemic for the period 2000-2013 and estimated the basic reproductive number R 0 . We then evaluated the effects of increasing treatment uptake (5-fold increase from the currently observed treatment rate of 0.22/person-year), or of increasing treatment efficacy on reducing the future HCV incidence. Finally, we evaluated the impact of three scenarios of future unsafe sex frequency on HCV incidence.

Poster Abstracts

420

CROI 2015