Title: Identification of social determinants of health influencing the compliance of TB treatment in Belgium and how to integrate these in the national TB policy Tuberculosis (TB) is a communicable airborne disease caused by Mycobacterium tuberculosis (Mtb), which is mainly transmitted through inhaled droplets. Pulmonary TB (PTB) accounts for about 80% of TB cases and is characterized by symptoms such as hemoptysis, chronic cough, and systemic issues like fever and weight loss, with potential spread to other body parts termed extrapulmonary TB (EPTB). Social determinants of health (SDH) have a great impact on TB, known as a social disease, as they influence exposure to infection, late or inappropriate diagnosis and treatment, progression to disease, and poor treatment adherence and success. In this thesis, we focus on the impact SDHs have on treatment adherence in low-incidence countries. In these countries, TB predominantly affects the most vulnerable and underserved groups. For instance, in Belgium, applicants for international protection and undocumented migrants make up a significant portion of TB cases, with especially high rates observed among residents of Brussels. In general, TB is more common in bigger cities in Belgium, so urban-risk groups are vulnerable and should be protected. Poor adherence has, in addition to the consequences for the individual patient also public health implications. It can lead to the development of drug-resistant TB (DR-TB) and long-term infectivity with increased risk of transmission. Therefore, to eliminate TB, maintaining adherence is essential. This thesis highlights that socio-economic factors, including income, employment, and housing instability, affect treatment adherence. Additionally, social support from family, community, and healthcare professionals is important for successful therapy completion. Furthermore, to enhance access to TB care and improve adherence, it is necessary to address issues such as racism, language barriers, stigma, mental health concerns, and challenges related to substance abuse. Lastly, providing stable housing during treatment and educating both patients and healthcare providers about TB and its treatment is important. Besides identifying SDHs of treatment adherence, this thesis gives examples of interventions that address these and calls for a national TB strategy that includes political commitment and multisectoral partnerships to effectively tackle these SDHs. Thereby, this thesis aligns with the view that ending TB requires a biosocial approach, integrating both social and medical strategies tailored to meet each patient’s individual needs. Student: Elles Panen Supervisor(s): Dr. Maja Kiselinova, Prof. Dr. Steven Callens