Related Experiment Video
Updated: Oct 23, 2025

Oral Combinational Antiretroviral Treatment in HIV-1 Infected Humanized Mice
Published on: October 6, 2022
Is event-driven PrEP dosing for HIV as effective as daily dosing?
Tory Olsen1, Zachary Lally-Montgomery1, Gary Kelsberg1
1Valley Family Medicine Residency, University of Washington at Valley, Renton.
Abstract:
PROBABLY, although there are no head-to-head trials comparing the 2 dosing regimens. Event-driven pre-exposure prophylaxis (PrEP) dosing reduces HIV conversion by 86% compared to placebo (strength of recommendation [SOR]: B, large randomized controlled trial [RCT]). Daily PrEP reduces HIV conversion by 44% to 86% (SOR: B, based on open-label RCTs).Event-driven PrEP regimens may be associated with lower adherence when compared with daily PrEP regimens (average of 70% for event-driven PrEP vs average of 92% for daily PrEP) (SOR: B, based on open-label and cohort trials). Event-driven PrEP regimens have lower medication costs, and they are associated with no difference in the rate of sexually transmitted infections (STIs) (SOR: B, based on prospective cohort studies). Patients may prefer them to daily regimens (75% choose event driven PrEP vs 25% choose daily PrEP) (SOR: BB, based on the preponderance of prospective cohort studies with conflicting results).
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