TY - JOUR T1 - How can we achieve better prevention of progression to tuberculosis among contacts? JF - European Respiratory Journal JO - Eur Respir J SP - 1743 LP - 1746 DO - 10.1183/09031936.00187112 VL - 42 IS - 6 AU - Steffen Geis AU - Gudrun Bettge-Weller AU - Udo Goetsch AU - Oswald Bellinger AU - Gisela Ballmann AU - Anja M. Hauri Y1 - 2013/12/01 UR - http://erj.ersjournals.com/content/42/6/1743.abstract N2 - To the Editor:Strategies for control and elimination of tuberculosis (TB) in low-incidence settings are directed toward treatment of recently acquired latent tuberculosis infection (LTBI) in TB contacts [1]. To identify this target population for preventive treatment the development of more specific, in vitro assays for LTBI, the interferon (INF)-γ release assays (IGRAs), has offered an alternative method for LTBI diagnosis. Although IGRAs are increasingly recommended in national guidelines, evidence that positive IGRA results are prognostic for developing TB is still limited [2, 3], especially outside of prospective studies with well-defined inclusion criteria. Therefore, we investigated progression towards active TB among IGRA positive contacts of active TB cases under routine field conditions and calculated the positive predictive value (PPV) for progression and the number needed to treat (NNT) with preventive treatment to prevent one incident TB case. Additionally, we introduced different cut-off values for IGRA positivity and compared the computed progression rates. Among all contacts with a positive tuberculosis-specific IGRA we describe the uptake of preventive treatment.Our study covered a population of 3.2 million with a reported TB incidence of 7.5 cases per 100 000 population in 2008. From 2008 to 2010, we prospectively recruited all IGRA-positive contacts of newly detected sputum smear and/or culture positive notified TB cases at 12 local public health authorities (LPHAs) in Hesse, Germany. Only contacts with a history of TB disease were excluded.The German recommendations for contact investigations, published in 2007 [4], served as the basis for the LPHAs investigations: a dual-step approach in which IGRA is only performed if the tuberculin skin test (TST) is positive. However, LPHAs deviated from this recommendation and performed TST in less than 27% of all IGRA tested contacts. All our study participants, namely all IGRA-positive contacts, were … ER -