Prevalence of primary HIV drug resistance among seroconverters during an explosive outbreak of HIV infection among injecting drug users

Objectives: This study examined the frequency of transmission of drug resistant HIV in the population of injecting drug users (IDU) in Vancouver, Canada during a period of particularly high virus transmission. Design: All subjects enrolled in the Vancouver Injection Drug Users Study who seroconverted from HIV negative to positive status (n = 61) between December 1996 and February 1998 were eligible for analysis. The first seropositive sample from 57 individuals with plasma samples available was analyzed for resistance to antiretroviral agents by population based sequencing of the HIV protease and reverse transcriptase genes. Methods: Plasma viral RNA was extracted and the viral reverse transcriptase and protease regions were amplified by nested reverse transcription-PCR. The presence of mutations associated with antiretroviral drug resistance was assessed by automated sequence analysis. Results: Protease and reverse transcriptase sequences were successfully obtained from the 57 recent seroconverters. No cases of transmission of variants associated with significant resistance to protease inhibitors or nucleoside and non-nucleosides reverse transcriptase inhibitors were detected. Conclusion: The frequency of transmission of drug resistant HIV amongst these recently infected IDU is extremely low, with no protease or reverse transcriptase inhibitor resistant strains detected soon after seroconversion. The data provide no rationale for withholding treatment from this already marginalized population. (C) 1999 Lippincott Williams & Wilkins.