Impact of annual TB screening on stone quarry workers in high-incidence Portuguese municipalities

Abstract

<sec id="st1"><title>SETTING</title>The Portuguese municipalities of Penafiel and Marco de Canaveses are high TB incidence areas, where stone quarry workers represent a vulnerable population.</sec><sec id="st2"><title>OBJECTIVE</title>To assess the annual rate of TB infection (ARI) in stone quarry workers and to compare it with the TB notification rate in the general community.</sec><sec id="st3"><title>DESIGN</title>An annual TB infection screening strategy using interferon-gamma release assay (IGRA) was implemented in 2018 for workers from high-risk stone quarries. A prospective cohort was enrolled and workers screened in periods of 2 years were included. IGRA-positive workers were referred for preventive treatment. ARI was calculated as the proportion of workers with IGRA conversion.</sec><sec id="st4"><title>RESULTS</title>Of the 232 IGRA-negative workers in 2018, 20 tested positive in 2019 (8.6% ARI). Of 171 IGRA-negative workers in 2019, eight tested positive in 2021 (4.7% in 2 years). Two of the 150 IGRA-negative workers in 2021 tested positive in 2022 (1.3% ARI). ARI decreased by 84.9% between 2019 and 2022. In the two municipalities, the TB notification rate declined 23.9% between 2018 and 2021.</sec><sec id="st5"><title>CONCLUSION</title>A more pronounced reduction in ARI was observed among stone quarry workers regularly screened for TB infection compared to the notification rate among the general population in high-incidence municipalities. A screening strategy for high-risk populations, together with enforced community measures, could foster risk reduction in the community.</sec>