Notable transmitted HIV drug resistance among people who inject drugs in Pakistan

Transmission of drug-resistant HIV strains to treatment-naive patients can compromise antiretroviral therapy (ART) effectiveness and lead to treatment failure. In Pakistan, transmitted HIV drug resistance among people who inject drugs (PWID) is fuelled by a lack of ART, poor drug adherence, and unsafe injection practices, resulting in efficient transmission in large injecting networks. A cross-sectional study was conducted among PWID recruited in the Pakistani cities of Karachi, Larkana, Peshawar, Quetta and Hyderabad (August 2014 to January 2015). A portion of the HIV pol gene was amplified from HIV-reactive dried blood spot specimens (n=282/367) and sequenced using an in-house Sanger sequencing assay for HIV drug resistance mutation genotyping. Drug resistance mutations (DRMs) were identified using the Stanford University HIV Drug Resistance Database HIVdb algorithm (https://hivdb.stanford.edu/hivdb). Overall, HIV subtype A1 was dominant (78.0%; n=220), followed by CRF02_AG (15.6%; n=44), CRF35_AD (2.5% n=7), recombinants (3.5%; n=10), and subtype C (0.4% n=1). DRM analysis identified over half (63.8%) of participants harbored at least one DRM, of which 28.9% reported using help from a professional injector. Nearly all (99.4%) participants were not actively receiving ART because most (88.7%) had never undergone HIV testing and were unaware of their status. Findings suggest significant transmitted HIV drug resistance present among PWID, exacerbated by unsafe injection practices, particularly professional injection. Low testing rates signal a need for more comprehensive testing programs to improve HIV status awareness and ART coverage in Pakistan. Given most treatment-naive participants had evidence of drug resistance, drug resistance genotyping prior to ART initiation might aid in ensuring effective treatment to prevent transmission of resistant HIV strains.