Le mercredi 17 septembre 2025, Madame Majdouline EL MOUSSAOUI, titulaire d'un Master en médecine et d’un Certificat de formation à la recherche en sciences médicales, présentera l'examen en vue de l'obtention du grade de Doctorat en sciences médicales, sous la direction de Monsieur Vincent BOURS et de Monsieur Gilles DARCIS.

Cette épreuve consistera en la défense publique d'une thèse intitulée : «Contribution to the Understanding of Chronic Infections and Immune Responses to Vaccines in Immunocompromised Individuals, including People with HIV». 

Le jury sera composé de :

Michel MOUTSCHEN (Président), Anne VAN DEN BROEKE (Secrétaire), Vincent BOURS, Gilles DARCIS, Keith DURKIN, Arnaud MARCHANT (ULB), Nicolas NOËL (Univ. Paris Sarclay).

Résumé de la thèse

Immunocompromised patients are at increased risk for chronic infections and may exhibit suboptimal immune responses to vaccination due to their altered immune systems. This research investigates these phenomena through clinical and experimental approaches, aiming to enhance our understanding of viral evolution and immune responses in this vulnerable population. The first objective of the thesis focused on the intrahost evolution and genetic diversity of SARS-CoV-2 in chronically infected immunocompromised patients. We prospectively sequenced SARS-CoV-2 at multiple time points, providing new insights into intrahost viral evolution dynamics and highlighting the limitations of nasopharyngeal samples in capturing the full viral diversity within the host. The second part of the thesis characterizes humoral and T-cell immune responses in immunocompromised individuals, with a particular focus on people living with HIV (PLWH). During the COVID-19 pandemic, booster doses were recommended for immunocompromised individuals, yet immune responses in this population were poorly understood. Additionally, we explored immune responses in PLWH at heightened risk for monkeypox infection.  This thesis contributes to understanding the immunological challenges faced by immunocompromised individuals in the context of chronic infections, emerging infectious diseases and evolving viral variants.