Social Risk Factors for Pulmonary Tuberculosis Vulnerability in Low- and Middle-Income Countries: A Systematic Review (2015–2025)

This systematic review examines the social risk factors associated with vulnerability to pulmonary tuberculosis (TB) in low- and middle-income countries (LMICs) between 2015 and 2025. Background and rationale. Pulmonary TB remains a leading infectious cause of death in LMICs and disproportionately affects socially and economically vulnerable populations. Although social determinants are increasingly recognised as drivers of TB vulnerability, individual social risk factors have largely been studied in isolation. No review to date has comprehensively synthesised the full range of social risk factors across LMIC regions within a unified framework, nor examined how the COVID-19 pandemic may have compounded these determinants. Objectives. Using the PECO framework, the review addresses three questions: (1) which social risk factors are most consistently associated with pulmonary TB vulnerability in LMICs; (2) whether and how these factors vary across four LMIC regions (Sub-Saharan Africa, South Asia, Southeast Asia, and Latin America); and (3) how the COVID-19 pandemic (2020–2022) influenced these social risk factors. Methods. The review is conducted and reported in accordance with the PRISMA 2020 statement. Systematic searches were performed in Scopus and PubMed (MEDLINE) for peer-reviewed, English-language, open-access journal articles published between 2015 and 2025. Eligible studies include observational (cohort, case-control, cross-sectional), qualitative, and mixed-methods designs reporting at least one social risk factor and a pulmonary TB outcome (incidence, prevalence, risk, diagnostic or treatment-seeking delay, treatment outcome, or mortality) in populations aged ≥15 years. Records are screened in Rayyan, methodological quality is appraised using the design-specific JBI critical appraisal checklists, and findings are synthesised narratively following the SWiM guideline, organised thematically and by region. Expected outcomes. The review is expected to identify the categories of social risk factors most consistently linked to pulmonary TB vulnerability, characterise regional heterogeneity in these profiles, assess the available evidence on the compounding effects of COVID-19, and highlight research and policy gaps relevant to the WHO End TB Strategy and the Sustainable Development Goals.