Role of the QuantiFERON(R)-TB Gold In-Tube assay in screening new immigrants for tuberculosis infection.

This study aimed to estimate the risk of progression to active tuberculosis (TB) within 2 yrs after entry in newly arriving immigrants who were screened with the QuantiFERON®-TB Gold In-Tube assay (QFT-GIT; Cellestis, Carnegie, Australia). In a case-base design, we determined the prevalence QFT-GIT-positive subjects among a representative sample of immigrants aged ≥ 18 yrs who arrived between April 2009 and March 2011 (the base cohort). Active TB patients (cases) within 2 yrs post-arrival in 2005, 2006 or 2007 were extracted from the Netherlands Tuberculosis Register. The risk of progression to active TB was estimated using Bayesian analyses to adjust for the sensitivity of QFT-GIT. Among the base cohort, 20% of 1,468 immigrants were QFT-GIT positive. Stratified by TB incidence in the person's country of origin as low (<100 cases per 100,000 population), intermediate (100-199 cases per 100,000) or high (≥ 200 cases per 100,000), the risk of progression to active TB per 100,000 arriving immigrants if QFT-GIT positive (95% credibility interval) was 456 (95% CI 307-589), 590 (397-762) and 386 (259-499), respectively, compared with 18 (0-46), 38 (0-97) and 28 (0-71) if QFT-GIT negative. Screening newly arriving immigrants with QFT-GIT contributes to detecting those at high risk of subsequent TB reactivation within 2 yrs after entry, which offers opportunities for prevention by targeted interventions.

Missed opportunities in tuberculosis control in The Netherlands due to prioritization of contact investigations.

BACKGROUND: The Dutch contact investigation guidelines stipulate that Public Health Services should examine contacts around all pulmonary tuberculosis (TB) patients to prevent disease and further transmission. Our objective was to assess to what extent these guidelines were applied and whether patient characteristics were associated with having contacts investigated. METHODS: We extracted the records of all reported pulmonary TB patients from the nationwide surveillance register covering 2006-07. Patient characteristics associated with having contacts investigated were assessed by multivariable logistic regression analysis. RESULTS: Out of the 1236 pulmonary TB patients reported, 909 (74%) patients were eligible for analysis, since 133 (11%) patients had incomplete records and 194 (16%) patients were registered by Public Health Services who did not report contact investigation results. For 710 (78%) out of the 909 patients contacts were investigated. Compared with Dutch patients, contacts were significantly less often investigated around immigrant patients (84 vs. 75%, OR: 0.60; 95% CI: 0.40-0.92). Contacts were significantly more often investigated for smear positive patients (OR: 3.52; 95% CI: 2.23-5.55) and culture positive patients (OR: 2.71; 95% CI: 1.76-4.16), compared with smear negative and culture negative patients, respectively. CONCLUSION: Initiating contact investigations appear to be prioritized based on the infectiousness, but also on the ethnicity of pulmonary TB patients. By not investigating the contacts of 25% of the immigrant patients, there is a risk of missing a significant number of infected and diseased contacts, since the incidence in this group is markedly higher than in the Dutch population.