Appropriate usage of post-exposure prophylaxis-in-pocket for HIV prevention by individuals with low-frequency exposures.

PEP-In-Pocket (Post-Exposure Prophylaxis-In-Pocket, or "PIP") is a biobehavioural HIV prevention strategy wherein patients are proactively identified and given a prescription for HIV post-exposure prophylaxis (PEP) medications to self-initiate in case of high-risk exposures. We evaluated this strategy in a prospective observational study at two hospital-based clinics in Toronto, Canada. HIV-negative adults using PIP underwent chart review and completed quarterly electronic questionnaires over 12 months. The primary objective was to quantify appropriate PIP initiation, defined as starting PIP within 72 h of a high-risk exposure. Secondary objectives were to quantify HIV seroconversions, changes in sexual risk behaviour, sexual satisfaction, and satisfaction with the PIP strategy. From 11/2017 to 02/2020, 43 participants enrolled and completed ≥1 questionnaire. PIP was self-initiated on 27 occasions by 15 participants, of which 24 uses (89%) were appropriate, 2 were unnecessary, and 1 was for an unknown exposure. Chart review identified no inappropriate non-use. Over 32 person-years of testing follow-up, we observed zero HIV seroconversions. Sexual risk declined modestly over follow-up, with a HIRI-MSM (HIV Incidence Risk Index for MSM) change of -0.39 (95% CI = -0.58, -0.21 per 3 months, p < .001). Sexual satisfaction was stable over time. At 12 months, 31 (72%) remained on PIP, 8 (19%) had transitioned to pre-exposure prophylaxis and 4 (9%) were lost-to-follow-up. Among participants who remained on PIP and completed questionnaires at 12 months, 24/25 (96%) strongly/somewhat agreed that PIP decreased their anxiety about contracting HIV and 25/25 (100%) strongly/somewhat agreed that they would recommend PIP to a friend. PIP is a feasible HIV prevention strategy in carefully selected individuals at modest HIV risk.