Retrospective analysis of TB screening in vulnerable populations in low-burden settings

BACKGROUND In high-income countries, TB has a major impact on vulnerable populations. Active case-finding (ACF) strategies target these populations, allowing the identification of TB in asymptomatic individuals and improving the local epidemiological situation. OBJECTIVES To evaluate the impact of ACF and define the factors associated with a higher probability of presenting TB in vulnerable populations, we performed an observational, descriptive, and retrospective study. We analysed the results of ACF studies performed in vulnerable populations (social service users, drug users, and recent migrants from high-TB areas) in Barcelona between 2018 and 2024. RESULTS 10,149 records of vulnerable individuals were studied. Seventy-three people were diagnosed and treated for TB (0.72%). There was microbiological confirmation in 47 (64.4%). Resistance to isoniazid was detected in two cases (2.7%) and multi-drug resistance in six (8.2%). Treatment was completed in 64 (87.7%). Risk factors associated with TB were: age less than 30 years (prevalence ratio [PR] = 4.1; 95% confidence interval [CI]: 1.6-10.5), homelessness (PR = 4.0; 95% CI: 2.6-9.2), and being a migrant (PR = 6.2; 95% CI: 2.6-9.2), with residence less than 5 years (PR = 4.4; 95% CI: 2.1-9.2). CONCLUSION ACF targeting vulnerable populations allows the early detection of TB. Priority should be given to the study of groups at higher risk of developing TB, such as homeless people and recent migrants. .