National and regional analysis of HIV transmission dynamics in Morocco: a mathematical modelling study

Background The Middle East and north Africa have the fastest-growing HIV epidemic globally. We aimed to present a national and regional analysis of HIV transmission dynamics in Morocco, using a decade of data to characterise epidemic patterns. Methods In this mathematical modelling study, we parameterised the UNAIDS Modes of Transmission model using biological, behavioural, and programmatic data from 58 integrated biobehavioural surveys and national datasets provided by the Morocco Ministry of Health and Social Protection collected between 2010 and 2023 in Morocco. The model estimated incidence in 2025 by exposure category at the national level and across six priority regions (Casablanca-Settat, Fes-Meknes, Marrakech-Safi, Rabat-Sale-Kenitra, Souss-Massa, and Tangier-Tetouan-Al Hoceima) and quantified the impact of interventions. We also analysed cross-sectional and longitudinal treatment cascades. Findings New HIV infections declined from 3163 (95% uncertainty interval [UI] 2404-4110) in 2013 to 874 (715-1136) in 2025. Key populations in 2025 accounted for 80 & centerdot;2% (95% UI 41 & centerdot;1-100) of new infections: 42 & centerdot;3% (22 & centerdot;6-62 & centerdot;6) from men who have sex with men (MSM) networks, 37 & centerdot;0% (18 & centerdot;2-66 & centerdot;7) from heterosexual sex-work networks, and 0 & centerdot;9% (0 & centerdot;2-1 & centerdot;9) from people who inject drugs networks. MSM had the highest incidence rate (0 & centerdot;80% per person-year [95% UI 0 & centerdot;39-1 & centerdot;05]). Women comprised 37 & centerdot;4% (26 & centerdot;7-50 & centerdot;2) of new infections, 75 & centerdot;0% (59 & centerdot;2-86 & centerdot;7) of which were acquired from a spouse with transmittable HIV. We found subnational heterogeneity, with MSM contributing 30 & centerdot;1% (95% UI 14 & centerdot;3-51 & centerdot;1) of new infections in Marrakech-Safi to 80 & centerdot;8% (67 & centerdot;9-93 & centerdot;7) of new infections in Fes-Meknes. Achieving the UNAIDS 95-95-95 targets could reduce incidence by 52 & centerdot;8%, and a 50% increase in condom use could avert 39 & centerdot;8% of infections. Scaling up oral and injectable pre-exposure prophylaxis (PrEP) could further reduce incidence, depending on adherence and coverage. Longitudinal cascade analysis indicated strong antiretroviral therapy (ART) retention across nine major sites (Agadir, Beni Mellal, Casablanca, Fes, Marrakech [two sites], Nador, Oujda, and Rabat), with median rates of 91 & centerdot;0% (IQR 89 & centerdot;0-93 & centerdot;0) at 24 (+/- 3) months, 83 & centerdot;8% (77 & centerdot;1-88 & centerdot;3) at 36 (+/- 3) months, and 83 & centerdot;3% (71 & centerdot;4-89 & centerdot;0) at 48 (+/- 3) months. Median viral load suppression among individuals tested was 94 & centerdot;9% or higher in the 2015, 2016, and 2017 cohorts. Interpretation Morocco's epidemic appears to have contracted markedly and shifted towards MSM, with increasing regional heterogeneity. Sustained scale-up of testing, ART, condom use, and PrEP is essential to consolidate progress and advance towards HIV elimination. Funding Expertise France. Copyright (c) 2026 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.