Medication adherence, condom use and sexually transmitted infections in Australian preexposure prophylaxis users
HIV preexposure prophylaxis (PrEP) decreases risk of HIV acquisition; however, its efficacy is closely dependent on adherence. There is also concern that the preventive effect of PrEP may be offset by risk compensation, notably an increase in condomless anal sex.Design:
Multisite, open-label demonstration study that recruited people at current or recent risk of HIV infection in Melbourne, Australia.Methods:
Participants were recruited from three general practice clinics and one sexual health clinic in Melbourne and consented to take daily tenofovir/emtricitabine (TFV/FTC) for 30 months. Sexual practice data, HIV and sexually transmitted infection (STI) test results were collected at baseline and 3-monthly during follow-up. PrEP adherence was evaluated by self-report at clinical visits, online surveys, refill-based assessments and dried blood spot testing. We present a 12-month interim analysis.Results:
A total of 114 people were recruited. We observed a significant decline in condom use which occurred concomitantly with a significant increase in STIs over the first 12 months of PrEP. Incidence (per 100 person-years) of any STI was 43.2 and 119.8 at months 0–3 and 3–12, respectively [incidence rate ratio 2.77 (1.52, 5.56)]. Adherence to PrEP medication was high by all measures, including 6 month TFV/FTC levels in dried blood spot.Conclusion:
We found a significant reduction in condom use and an increase in STIs over the first 12 months of follow-up. High medication adherence rates occurring with a decline in condom use and a rise in STIs, suggest that prevention, early detection and treatment of STIs is a chief research priority in the current era of HIV PrEP.