Evaluation of systematic TB screening programs for immigrants as part of the EU TB-DETECT project
In a study published in October 2022, Menezes et al (1) analyze data from four large European tuberculosis (TB) screening programs for immigrant populations conducted in Italy, Sweden, the Netherlands and the UK, comparing the different program approaches, the populations studied and the case detection rates of the programs.
The study uses data collected as part of the "E-DETECT" project funded by the European Commission between 2005 and 2018. They include approximately 2.3 million screening events from a total of over 2 million immigrants, most of whom are young adults aged 18-44 (77.8%) from Asia (78%) and Africa (18%). A total of 1,658 TB cases were found during the period, with significant differences in case detection rates between the four countries. The UK has the lowest rate at 68.9 cases per 100,000 people screened, followed by the Netherlands with a case detection rate of 83.2/100,000, then Sweden with 201.1/100,000. Italy has the highest case detection rate at 653.6 cases/100,000.
These large differences can be partly explained by different approaches to TB screening programs and differing migration patterns. Although almost all low-incidence countries have prescribed regulations for TB screening of immigrants, these are not uniform. The various programs vary considerably in terms of target groups, testing procedures, implementation and whether screening is voluntary or not.
In Sweden, Italy and the Netherlands, for example, TB screening is carried out shortly after the arrival of the immigrants, whereas in the UK it is carried out in the country of origin. The groups examined also differ. While screening in the UK is limited to people who have already been granted a visa, in the other countries it is mainly asylum seekers who are included in the screening programs, while in the Netherlands other people with a history of immigration are also included. In Italy and Sweden, participation in the program is voluntary, in the Netherlands and the UK it is mandatory.
The type of test used also has an impact on case detection rates. In the UK, screening is carried out using symptom questionnaires and chest X-rays. In Sweden and Italy, on the other hand, tuberculin and IGRA tests are carried out first and an X-ray is only performed in the event of positive findings or the presence of symptoms. This more targeted screening method could have an influence on the higher case detection rates in Italy and Sweden.
Above all, however, the countries of origin and migration patterns play a decisive role in the number of TB cases found. The high number of cases in Italy is probably also due to the fact that comparatively more immigrants there come from Africa (83.6%), predominantly from high-incidence countries south of the Sahara. These are presumably also exposed to a very high risk of infection on their flight route to Europe.
The authors emphasize the importance of joint data collection and analysis, as well as conducting further studies with current and more comprehensive data to better understand the different case detection rates and identify the most appropriate screening method. The knowledge gained can help to make evidence-based policy decisions and develop standardized guidelines for TB screening of immigrants in the future to contribute to global TB elimination.
Significance for Germany: In Germany, according to the Infection Protection Act §36Abs.4, a certificate of freedom from TB is required from immigrants before admission to a community facility, which is usually based on a chest X-ray or other method approved by the state authorities. Coordinated by the DZK, an S3 guideline on prevention in immigrants is currently being developed that specifically examines the type, implementation and management of TB screening in Germany. Completion is planned by 2025.
- Menezes D, Zenner D, Aldridge R, Anderson SR, de Vries G, Erkens C, Marchese V, Matteeli A, Muzyamba M, Nederby-Öhd J, van Rest J, Spruijt I, Were J, Lönnroth K, Abubakar I, Cobelens F. Country differences and determinants of yield in programmatic migrant TB screening in four European countries. Int J Tuberc Lung Dis. 2022 Oct 1;26(10):942-948. doi: 10.5588/ijtld.22.0186
