Prevalence of Latent Tuberculosis Infection in Vulnerable Groups in the State of Santa Catarina, Brazil.

Abstract

Background: Tuberculosis remains a major public health challenge that exerts substantial pressure on healthcare systems worldwide. Despite advances in diagnosis and treatment, the proper management of latent tuberculosis infection (LTBI) remains inefficient, especially among vulnerable populations. In the State of Santa Catarina, Brazil, the absence of comprehensive and specific records on LTBI prevalence in these at-risk groups limits effective public health planning and interventions.

Methods: Interferon-gamma release assay (IGRA) test records in the State of Santa Catarina, Brazil, contained partial information on risk factors for LTBI. Multiple imputations were used to estimate the likely risk groups among individuals without such information. The study was approved by the Human Research Ethics Committee under protocol number CAAE 79499224.4.0000.5361.

Results: The estimated LTBI prevalence among individuals with available IGRA results was 6.89%, with higher rates among people living with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (18.25%) and immigrants (3.65%). Underreporting was notable among individuals deprived of liberty, those experiencing homelessness, those who use illicit drugs, and those with diabetes mellitus. Missing data were frequent among individuals living with HIV; people of African, Indigenous, or Asian descent; and those exposed to drug-resistant TB. More than 10% of LTBI cases occurred in children and adolescents aged <15 years.

Conclusion: HIV was the most prevalent risk factor among IGRA-positive individuals and was substantially underestimated. An urgent expansion of LTBI identification efforts is needed for all vulnerable populations, with special attention paid to children and adolescents who present a high risk of progressing to active TB.