Background: Prophylactic use of antiretroviral drugs among individuals at high risk of HIV infection constitutes a cornerstone for HIV eradication programs. The effectiveness of orally administered PrEP is however dependent on subjects'' adherence to the once daily dosing regimen. Demonstration projects in Senegal, Kenya and Nigeria have been implemented to test the feasibility, scalability and effect of measurement-guided adherence-enhancing interventions in resource-limited settings. This abstract focuses on the project conducted in Senegal.
Methods: The program has been conducted among female sex workers in 4 Ministry of Health (MoH)-run clinics in Dakar, Senegal. An Integrated Next Step Counseling (iNSC) was used for adherence counseling to optimize exposure to prophylaxis. The iNSC is a strengths-based discussion focused on PrEP adherence needs and tailored strategies to support individuals. The iNSC has been extended to rely on reliable and precise measure of medication adherence using Medication Event Monitoring System (MEMS). MEMS timestamped each opening of a medication package, providing a sound proxy for medication intake. Resulting dosing history data were used as individual feedback during the adherence counseling. The effect of this adherence-enhancing intervention is quantified and tested using longitudinal logistic regression models.
Results: Between July and November 2015, 350 individuals were identified, 321 (91.7%) were preliminarily eligible, and 267 (83.1%) were enrolled for up to 12-months of PrEP. 181 subjects were electronically monitored and entitled to receive extended iNSC counseling sessions.
According to MEMS data, an estimated 63% of the subjects took their medication daily as prescribed during the month preceding the first intervention, with large disparities between centers ranging from 51% to 76%.
The odds of taking the drug daily as prescribed after intervention was twice the odds pre-intervention (Odds Ratio 2.06, 95% CI 1.57-2.70; p < 0.001). Therefore, daily, the proportion of subject adherent to the prophylaxis was 17% higher after receiving extended iNSC counseling.
Conclusions: These results suggest the feasibility of adherence counseling sessions using adherence data as feedback in resource-limited settings. They also show the effect of the extended iNSC intervention on adherence to PrEP prophylaxis. Further analyses on the effect of recurrent interventions and their effect over time are ongoing.

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