The key learning outcomes I gained from this session were:
- The development of drug resistance is relatively uncommon
- When drug resistance does occur, it is usually the result of prolonged PrEP use (I.e. greater than 2-4 weeks)
- The majority of resistance is to Emtricitabine. Fortunately, resistance to Tenofovir is rare
- More rigorous monitoring of individuals with recent high-risk behaviour is important when considering PrEP
This particular presentation resonated with a recent clinical experience we had at our service. The patient had been commenced on PrEP by a primary care provider. The issue was that the patient commenced PrEP without a rapid HIV test and the laboratory HIV test that was sent away was just prior to the Easter holiday period. The positive result took a total of 11 days to return after the confirmatory assays were performed. Therefore, the patient had already been taking PrEP for almost 2 weeks. We were concerned about the possibility of resistance and in particular Tenofovir resistance and as a result hesitated to initiate antiretroviral therapy until the genotype resistance assay returned a few weeks later. Fortunately, there was no evidence of drug resistance. This presentation reaffirmed to us that resistance is relatively uncommon, especially with less than 4 weeks of PrEP use. It was also reassuring to know that our initial concern regarding Tenofovir resistance was highly unlikely. If I were to encounter a similar scenario in the future I do not think I would hesitate to commence a robust single tablet regimen, especially if the patient has been on PrEP for less than 4 weeks. In order to improve engagement and to facilitate same-day PrEP, I would like to have a rapid HIV test on all individuals wishing to commence PrEP. For individuals with recent high-risk behaviours, I would perform a qualitative HIV RNA test where feasible or at the least request earlier follow up, perhaps at 1 month to account for any individuals that may have been within the window period at initial presentation.
Author bio: I am a new (first year) Advanced Trainee in Sexual Health and HIV Medicine. I recently completed Basic Physician Training last year. My previous undergraduate background has been in pathology working as a medical scientist in microbiology and haematology. I am currently working in the Sexual Health and HIV clinic at Biala (Royal Brisbane Hospital) and attending this conference would provide an invaluable experience for my clinical practice.
