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Session 95 Poster Abstracts
Transmission of Drug Resistant HIV-1: Conflicting Trends and Clinical Significance
Monday, 1:30 - 3:30 pm
Poster Hall


683
Changes in Prevalence and Characteristics of Transmitted Resistance over Time among European Seroconverter Cohorts
B Masquelier*1, D Pillay2, L van der Hoek3, M Prins4, E Balestre5, C Nielsen6, C Pedersen7, J del Romero8, M Ortiz9, C Balotta10, G Rezza11, R Gifford2, K Porter12, and the CASCADE Virology Collaboration
1Hosp. Pellegrin, Bordeaux, France; 2Univ. Coll. London, UK; 3Academic Med. Ctr., Amsterdam, The Netherlands; 4GGGD, Amsterdam, the Netherlands; 5ISPED, Bordeaux, France; 6SSI, Copenhagen, Denmark; 7Odense Univ. Hosp., Denmark; 8Sandoval Clin., Madrid, Spain; 9ISC III, Valencia, Spain; 10IITD, Milan, Italy; 11ISS, Rome, Italy; and 12MRC CTU, London, UK

Background: The prevalence of transmitted drug resistant HIV has increased since HAART became available, potentially compromising the efficacy of therapy. As the time of HIV seroconversion is rarely known and because any resistance-associated mutations present at seroconversion may revert to wild type over time in the absence of drug pressure, there is a need for international efforts to pool all available data on transmitted drug resistant in seroconverters to monitor trends over time and examine correlates associated with transmitted drug resistant.

Methods:  We pooled data from 12 studies in Europe of persons genotyped within 18 months of a negative HIV antibody test while naïve to ART.  We describe overall prevalence and trends over time and examine whether any change in prevalence is due to resistance to one class or to multi-class resistance.

Results:  Data were available on 370 individuals who seroconverted between 1987 and 2002 (median year of seroconversion, 1998), of whom 91% were infected with subtype B virus.  43 (11.7%) were infected with transmitted drug resistant all of whom seroconverted in 1995 or later. We found no evidence to suggest that transmitted drug resistant was associated with gender (p = 0.3), age (p = 0.8), or exposure category (p = 0.5). From 1995 there was no evidence of a change in prevalence of transmitted drug resistant over time (p-trend = 0.9), although a peak of 20% (12/61) was noted in 2000. The proportion with transmitted drug resistant rose from 10.5% in 1995 to 19.7% in 2000 and fell to 9.1% in 2002.  Of those with transmitted drug resistant, 37 had mutations conferring resistance to one class (26 to NRTI, 5 to NNRTI, and 6 to PI). Of the 6 individuals with transmitted drug resistant to more than one class, one was resistant to all 3 current classes of ART.

Conclusions:  We identify transmitted drug resistant  in >10% of recent infections across Europe.  Nucleoside analogue resistance is the most common manifestation of this phenomenon, and MDR viruses are rare. The epidemiological impact of transmitted drug resistant within Europe requires investigation.

Keywords: transmitted resistance; seroconverters; prevalence