Transmission of HIV drug resistance: lessons from sensitive screening assays

Purpose of review The review discusses new technologies for the sensitive detection of HIV drug resistance, with a focus on applications in antiretroviral treatment (ART)-naïve populations. Recent findings Conventional sequencing is well established for detecting HIV drug resistance in routine care and guides optimal treatment selection in patients starting ART. Access to conventional sequencing is nearly universal in Western countries, but remains limited in Asia, Latin America, and Africa. Technological advances now allow detection of resistance with greatly improved sensitivity compared with conventional sequencing, variably increasing the yield of resistance testing in ART-naïve populations. There is strong cumulative evidence from retrospective studies that sensitive detection of resistant mutants in baseline plasma samples lacking resistance by conventional sequencing more than doubles the risk of virological failure after starting efavirenz-based or nevirapine-based ART. Summary Sensitive resistance testing methods are mainly confined to research applications and in this context have provided great insight into the dynamics of drug resistance development, persistence, and transmission. Adoption in care settings is becoming increasingly possible, although important challenges remain. Platforms for diagnostic use must undergo technical improvements to ensure good performance and ease of use, and clinical validation is required to ensure utility.