Report on the Epidemiology of Tuberculosis in Germany - 2017

full report in German

In 2017, a total of 5,486 tuberculosis (TB) cases were notified in Germany. This corresponds to an annual TB incidence of 6.7 cases per 100,000 population. Thus, after the significant increase in case numbers in 2015 (5,834 cases, incidence 7.1) and the almost unchanged situation in 2016 (5,949 cases, incidence 7.2) case numbers are now declining again, but remain at a comparatively high level.

Analysis of demographic data: Tuberculosis incidence was 9.1 cases per 100,000 population in men and 4.3 in women (male to female ratio of 2.1). The age-specific incidence was highest in the age group 20-24 years (18.2 cases per 100,000 population; 25.4 in men and 10.1 in women).

Citizenship: Tuberculosis incidence in foreign nationals residing in Germany was 18 times higher than the incidence in German citizens (40.6 vs. 2.2 cases per 100,000 population, respectively). The largest difference was observed in young adults. Overall, Germans comprised of 31.9 % of all tuberculosis cases, whereas the remaining 68.1 % of all cases were foreign nationals. Foreign nationals affected by tuberculosis were younger than German nationals (median age: 27 vs. 60 years).

The analysis by country of birth showed that the proportion of foreign-born patients, which has risen steadily in recent years and accounts for almost three-quarters of all patients, decreased in 2017 (72.6 %). It was 1.7 % lower compared to the previous year (2016: 74.3 %). The most frequently registered foreign countries of birth in 2017 were Eritrea and Somalia.

Tuberculosis in children: A total of 238 cases were reported in children younger than 15 years of age (incidence 2.2 cases per 100,000 children). There was a slight increase of 10 cases compared to 2016 (228 cases; incidence 2.2 per 100,000 children). Tuberculosis incidence was highest in the youngest age group below five years of age (131 cases; incidence 3.6 per 100,000). In children aged 5 to 9 years, the incidence of TB was 1.2 per 100,000 (42 cases), while in children aged 10 to 14 years, it was 1.8 per 100,000 (65 cases). Tuberculosis incidence in children of foreign nationality was almost 16 times higher in comparison to German children (14.5 vs. 0.9 per 100,000 population).

Case finding: The proportion of tuberculosis cases detected by active case finding was 18.4 % in 2017 (862 cases); this increase was mostly due to active case finding among asylum seekers in accordance with paragraph 36 of the IfSG (German Protection Against Infection Act). In comparison to previous years, the numbers found through active case finding were lower (2016: 1,282 cases, 24.7 %; 2015: 1,490 cases, 29.1 %) since fewer cases were registered by screening. The proportion of tuberculosis detected by contact tracing was 6.0 % in 2017 (280 cases). It continues to remain high especially among children (48.3 %).

Site of disease: Pulmonary tuberculosis was diagnosed in 73.9 % of cases (3,892 cases; incidence 4.7 per 100,000) and was potentially infectious (sputum-smear or culture positive) in the majority of cases (3,133 cases, incidence 3.8) in comparison to non-infectious pulmonary tuberculosis (759 cases; incidence 0.9). Of the pulmonary TB cases, 43.4 % (1,690/3,892) were smear positive and, thus, were the most infectious cases. Extra-pulmonary tuberculosis solely was diagnosed in 1,375 cases (26.1 %). In about half of these extra-pulmonary cases, the main affected site was the lymph node (718 cases; 52.2 %).

Drug-resistant tuberculosis: The proportion of multidrug-resistant tuberculosis (MDR-TB) was 3.0 % (109 cases) in 2017, and slightly higher than in 2016 (2.7 %, 107 cases).

The proportion of MDR-TB was highest in patients born in one of the newly independent states (NIS) of the former Soviet Union (19.3 % compared to 1.0 % in German born patients). Four extensively drug-resistant TB cases were notified in 2017. The overall proportion of TB cases resistant to at least one of the five standard anti-TB drugs (isoniazid, rifampicin, ethambutol, pyrazinamide, and streptomycin) was 11.9 % in 2017, which was slightly lower than in 2016 (12.4 %). The proportion of »any drug-resistant« TB cases was higher among patients born in an NIS country in comparison to those born in Germany (31.3 % vs. 8.3 %, respectively).

Deaths: A total of 102 patients died of tuberculosis in 2017. This corresponded to a mortality rate of 0.12 cases per 100,000 population. The case fatality rate was 1.9 %.

Treatment outcome can only be assessed after at least 12 months of follow-up and is, therefore, reported here for cases notified in 2016. The completeness of treatment outcome reporting was 84.5 % (5,025 of 5,949 reported cases). Among patients with available information, 80.9 % (4,067 cases) were treated successfully, 9.9 % (497 cases) experienced an unsuccessful treatment for different reasons, 4.8 % (243 cases) were still on treatment, and 4.3 % (218 cases) were reported as having transferred out. Treatment outcome showed age-specific differences with a higher proportion (>85 %) of treatment success reported for children and younger patients; this proportion declined in older age groups. For patients aged 80 years or older, only 53.6 % completed treatment successfully.

Conclusion: Detailed analysis of notification data shows that the tuberculosis situation in Germany is mainly influenced by migratory movements and demographic changes in the population.

Following the significant increase in tuberculosis in 2015 and almost identical case numbers in 2016, a slight decline in numbers was observed in 2017. The reported case numbers are directly related to the legally required active case finding for refugees and asylum seekers, which is therefore an important tool for early case detection.

In Germany, however, most cases of tuberculosis are still diagnosed by passive case finding. This also affects many patients who were born abroad, as the risk of developing active disease remains higher years after entry. Around a quarter of tuberculosis patients diagnosed in Germany were

born in Germany. Most of them are older people who became infected with TB in the war or postwar years and did not develop active tuberculosis until later in life. This highlights the importance of maintaining continued vigilance against TB and the consideration for differential diagnosis.

The slight increase in the number of cases among young children requires particular attention, not only because of their vulnerability, but also as an indicator of current transmission among the population.

The occurrence of multidrug-resistant and extensively drug-resistant tuberculosis is a challenge to tuberculosis control and also requires particular attention, with a focus on ensuring successful treatment outcomes including treatment follow-up.

High case numbers in the non-German population, multidrug-resistant and extensively drug-resistant TB, and a high proportion of infectious pulmonary TB indicate that TB remains a significant public health issue in Germany, mainly affecting risk groups.

The German TB-surveillance system is essential for timely identification of epidemiological trends and their interpretation in the context of factors that potentially influence the epidemiological situation. In addition to screening measures for asylum seekers, active case finding by means of contact tracing is also important so that infected persons and active cases can be identified as early as possible. Ensuring complete and successful therapy, including timely and accurate notification of treatment outcomes, is essential for ongoing effective tuberculosis control in Germany and requires a coordinated approach and ongoing cooperation from all stakeholders.