In countries with low tuberculosis (TB) incidence, the systematic testing and treatment of latent TB infection (LTBI) in contacts of pulmonary TB index cases is the standard of care. The objective of this study, conducted in Catalonia over 2019-2021, was to assess the factors associated with LTBI treatment prescription to close contacts of pulmonary TB index cases. In this population-based epidemiological study of LTBI prevalence among pulmonary TB contacts between 2019 and 2021, multiple logistic backward stepwise regression was used to identify the factors associated with treatment prescription, for which the adjusted odds ratio (aOR) and 95% confidence intervals (CI) were calculated. A total of 1487 LTBI contacts of 542 pulmonary TB index cases were studied, 80.6% of whom received a prescription. The factors associated with LTBI treatment prescription were exposure ≥6 h/day (aOR 14.20; 95% CI 5.22-38.66) and exposure <6 h/day (aOR 7.32, 95% CI 2.48-21.64), whereas the factors associated with no LTBI treatment prescription were age ≥55 years (aOR 0.22, 95% CI 0.08-0.64) and bacillus Calmette-Guerin vaccination (aOR 0.38, 95% CI 0.16-0.90). Crucial to LTBI treatment prescription is information on the contact's duration of exposure to pulmonary TB, not only for contacts exposed for ≥6 h/day, but also for contacts with lower daily exposure levels.
Keywords: contact tracing; latent TB infection; prescription; prevention; treatment; tuberculosis.