Incidence of Latent Tuberculosis Infection (LTBI) Following Incarceration among New Prisoners.

Background: The occurrence of tuberculosis (TB) in prisoners is higher than in the general population. Objective: To determine the incidence of Latent tuberculosis infection (LTBI) in newly incarcerated persons in southern Thailand. Materials and Methods: A prospective cohort study was conducted between January 2020 and December 2020 in all new inmates aged 15 years or older. Within two weeks of imprisonment, chest radiography and the two-step tuberculin skin test (TST) were performed. Participants with a negative TST underwent a repeat one-step TST at six months. A positive TST at six months without evidence of TB indicated new LTBI. Results: Six hundred two male inmates were enrolled. Fifty-one prisoners (8.5%) were excluded due to a history of previous incarceration for 4.1%, history of TB for 0.8%, household contact with TB cases for 2.1%, and refusal to participate for 1.3%. The remaining 551 inmates participated in the study. The average age was 31.1 years. The two-step TST was completed in 507 inmates (92.0%). Two hundred thirteen out of 551 participants (38.7%) initially tested positive. Follow-up was conducted on 290 participants. Only 53 participants (9.6%) completed the study protocol at six months due to COVID-19 pandemic lockdown. Tuberculin conversion was found in five inmates (9.4%). Conclusion: LTBI prevalence and incidence rates among Thai inmates are high. Individuals with negative LTBI test at initial imprisonment were at high risk of acquiring infection and should be followed to detect conversion and offered LTBI treatment. [ABSTRACT FROM AUTHOR]