Impacto de triagens sistemáticas em massa na prevalência da tuberculose em prisões sul-mato-grossenses

Abstract

Introduction: Tuberculosis control in environments with high prevalence and incidence is a challenge. The effectiveness and optimal frequency of mass tuberculosis screening in high-risk populations, such as incarcerated people, constitutes an important knowledge gap. Methods: Three rounds of mass screening were carried out in three prisons in the state of Mato Grosso do Sul, Brazil, from November 2017 to September 2021. Standardized questionnaires on health and socio-demographic data, symptom screening, systematic sputum collection for Xpert® MTB RIF test and culture, and chest x-ray with CAD4TB score were administered to all incarcerated persons. We assessed the prevalence of tuberculosis per 100,000 people and the proportion of subclinical tuberculosis overall and in each prison across several rounds of screening. Results: The prevalence of tuberculosis from the 1st to the 3rd round of screening was 4,000 (214 cases/5,349 people), 3,730 (216 cases/5,790 people) and 4,370 (254 cases/5,815 people) per 100,000 people. The change in prevalence from round 1 versus 3 of screening was distinct among prisons with similar levels: EPJFC (+16%; 5583 versus 6474, P=0.2465), increases in prevalence in IPCG (+89%; 2475 versus 4689, P=0.0019) and in PED (-40%; 3.620 versus 2.190, P=0.0043). From round 1 versus 3, there was a decrease in the proportion of tuberculosis cases diagnosed with either cough (71% versus 24%, P<0.0001), chronic cough (54% versus 16%, P<0.0001), or any tuberculosis-related symptom (79% versus 29%, P<0.0001). Among diagnosed cases, the mean value of the semiquantitative Xpert® load was lower in round 3 (1.7 [SD, 1.2]) compared to rounds 1 (2.4 [SD, 0.9]) and 2 (2.3 [SD, 1.0]). Conclusion: In this prison environment with hyperendemic rates of tuberculosis, three rounds of mass screening did not reduce the overall tuberculosis burden. However, the proportion of subclinical and asymptomatic disease increased over time, suggesting that intensive screening can reduce the patient's bacillary burden and therefore ongoing transmission.