25th HIV Drug Resistance Workshop
This is the second time I have attended this meeting. It was very different from last year. Considerable attention was paid to transmitted resistance in the context of PrEP. While this does occur, it does not appear to be persistent.
There were also a number of papers looking at the practical implications of resistance in treatment. A number of presenters reported that resistance may not render a regimen defective. There was discussion about the utility of testing and while resistance testing remains too costly for use in many settings, it was also suggested that many clinicians in developed settings perform resistance testing, but don’t use it in regimen selection. There was some suggestion that resistance testing is becoming less important in the context of newer therapies. One take home message was that the longer people are on treatment, the greater the likelihood to resistance.
Preserving 2nd and subsequent line therapy was seen as the major reasons for not switching, even in the absence of resistance testing, particularly in low and middle income settings.
Sequencing virus for epidemiological purposes is becoming increasingly important. A number of papers looked at clusters. It was suggested that some virus may be becoming more durable. With 30 clusters in one sample accounting for 1500 infections, while 1300 infections were seen as singleton transmissions. In this study the resistant virus was seen to be as fit as wild type virus. At a practical level what this means a new population is getting infected with lower sexual activity and with a lower testing frequency. There was also an interesting paper looking at clusters among injectors. The abstracts can all be found on line at https://www.informedhorizons.com/resistance2015/pdf/RW2015_Book.pdf