Prevalence and risk factors for latent tuberculosis infection among health care workers in Georgia

BACKGROUND: Tuberculosis (TB) is a major public health problem in Georgia, but few TB infection control measures have been implemented in health care facilities. OBJECTIVE: To assess the prevalence and risk factors for latent TB infection (LTBI) among Georgian health care workers (HCWs) using two diagnostic tests, the tuberculin skin test (TST) and the QuantiFERON (R)-TB Gold In Tube test (QFT-3G), an interferon-gamma release assay. METHODS: A cross-sectional study was conducted between June and August 2006 among HCWs at the Georgian National TB Program. RESULTS: Of 265 HCWs enrolled, 177 (67%) had a positive TST and 159 (60%) had a positive QFT-3G; 203 (77%) had a positive result for at least one of the tests and 50% tested positive for both tests. There was moderately good agreement between the tests (74%, kappa = 0.43, 95%CI 0.33-0.55). In multivariate analysis, employment for >5 years was associated with increased risk of a positive TST (OR 5.09, 95 % CI 2.77-9.3 3) and QFT-3G (OR 2.26, 95%CI 1.27-4.01); age >30 years was associated with an increased risk of a positive QFT-3G (OR 2.91, 95%CI 1.32-6.43). DISCUSSION: A high prevalence of LTBI was found among Georgian HCWs and longer duration of employment was associated with increased risk. These data highlight the need for effective TB infection control measures and provide important baseline information as TB infection control measures are implemented.