Imperial College London


Faculty of MedicineSchool of Public Health

Professor of Mathematical Epidemiology



+44 (0)20 7594 3263mc.boily




LG26Norfolk PlaceSt Mary's Campus






BibTex format

author = {Dimitrov, D and Moore, J and Wood, D and Mitchell, K and Li, M and Hughes, J and Donnell, D and Mannheimer, S and Holtz, T and Grant, R and Boily, MC},
doi = {cid/ciz799},
journal = {Clinical Infectious Diseases},
pages = {249--255},
title = {Predicted effectiveness of daily and non-daily PrEP for MSM based on sex and pill-taking patterns from HPTN 067/ADAPT},
url = {},
volume = {71},
year = {2020}

RIS format (EndNote, RefMan)

AB - Background: HPTN 067/ADAPT evaluated the feasibility of daily and non-daily HIV pre-exposure prophylaxis (PrEP) regimens among high-risk populations, including men who have sex with men (MSM) and transgender women, in Bangkok, Thailand and Harlem, New York, U.S. We used a mathematical model to predict the efficacy and effectiveness of different dosing regimens. Methods: An individual-based mathematical model was used to simulate annual HIV incidence among MSM cohorts. PrEP efficacy for covered sex acts, as defined in the HPTN 067/ADAPT protocol, was estimated using subgroup efficacy estimates from the iPrEx trial. Effectiveness was estimated by comparison of the HIV incidence with and without PrEP use.Results: We estimated that PrEP was highly protective (85%–96% efficacy across regimens and sites) for fully covered acts. PrEP was more protective for partially covered acts in Bangkok (71%–88% efficacy) than in Harlem (62%–81% efficacy). Our model projects 80%, 62%, and 68% effectiveness of daily, time-driven, and event-driven PrEP for MSM in Harlem compared with 90%, 85% and 79% for MSM in Bangkok. Halving the efficacy for partially covered acts decreases effectiveness by 8–9 percentage points in Harlem and by 5–9 percentage points in Bangkok across regimens. Conclusions: Our analysis suggests that PrEP was more effective among MSM in Thailand than in the U.S. as a result of more fully covered sex acts and more pills taken around partially covered acts. Overall, non-daily PrEP was less effective than daily PrEP, especially in the U.S. where the sex act coverage associated with daily use was substantially higher.
AU - Dimitrov,D
AU - Moore,J
AU - Wood,D
AU - Mitchell,K
AU - Li,M
AU - Hughes,J
AU - Donnell,D
AU - Mannheimer,S
AU - Holtz,T
AU - Grant,R
AU - Boily,MC
DO - cid/ciz799
EP - 255
PY - 2020///
SN - 1058-4838
SP - 249
TI - Predicted effectiveness of daily and non-daily PrEP for MSM based on sex and pill-taking patterns from HPTN 067/ADAPT
T2 - Clinical Infectious Diseases
UR -
UR -
VL - 71
ER -