International tuberculosis contact-tracing notifications in Germany: analysis of national data from 2010 to 2018 and...

International contact-tracing (CT) following exposure during long-distance air travel is resource-intensive, whereas evidence for risk of tuberculosis (TB) transmission during international travel is weak. In this study, we systematically analyzed the information from international requests for CT received at the national level in Germany in order to evaluate the continued utility of the current approach and to identify areas for improvement.

An anonymized archive of international CT notifications received by the Robert Koch Institute between 2010 and 2018 was searched for key parameters for data collection. A total of 31 parameters, such as characteristics of TB patients and their identified contacts, were extracted from each CT notification and collated into a dataset. Descriptive data analysis and trend analyses were performed to identify key characteristics of CT notifications, patients, and contacts over the years.

192 CT notifications, each corresponding to a single TB index case, were included in the study, increasing from 12 in 2010 to 41 in 2018. The majority of notifications (N = 130, 67.7%) concerned international air travel, followed by private contact (N = 39, 20.3%) and work exposure (N = 16, 8.3%). 159 (82.8%) patients had sputum smear results available, of which 147 (92.5%) were positive. Of 119 (62.0%) patients with drug susceptibility testing results, most (N = 92, 77.3%) had pan-sensitive TB, followed by 15 (12.6%) with multi-drug resistant TB. 115 (59.9%) patients had information on infectiousness, of whom 99 (86.1%) were considered infectious during the exposure period. 7 (5.3%) patients travelled on long-distance flights despite a prior diagnosis of active TB. Of the 771 contact persons, 34 (4.4%) could not be reached for CT measures due to lack of contact information.

The high variability in completeness of information contained within the international CT requests emphasizes the need for international standards for reporting of CT information. With the large proportion of TB patients reported to have travelled while being infectious in our study, we feel that raising awareness among patients and health professionals to detect TB early and prevent international long-distance travel during the infectious disease phase should be a cornerstone strategy to safeguard against possible transmission during international travel.