Eurosurveillance this week features articles for World Tuberculosis Day. An excerpt from the editorial: Ending tuberculosis in risk groups in Europe: Challenges from travel and population movement.
As many countries in Europe make progress in tuberculosis (TB) control, TB incidence in Europe is diverse; in low-incidence countries (those with an incidence less than 20 per 100,000) the TB burden is increasingly borne by specific risk groups, such as migrants from high- to lower-incidence countries, persons with social risk factors such as homelessness and individuals who have been in contact with a TB patient. Strategies to control TB within these risk groups include screening for active disease and sometimes latent infection, followed by treatment where appropriate.
The effectiveness of screening strategies to identify patients needing treatment varies. For example, the yield of active TB among migrants from high- to low-burden countries ranged from 7 to 10,186 per 100,000 people screened, depending on various factors including the TB prevalence in the country of origin. In this World TB Day issue of Eurosurveillance, four papers describe the risks of TB infection and disease in two potentially high-risk groups: migrants and airline passengers.
Migrants are considered to be at high risk of TB, for reasons such as the possibility of reactivation of latent infection acquired in their home country, frequent travel to high-incidence areas, and perhaps transmission within migrant communities in the receiving countries.
At European Union (EU) level, Hollo et al. report that TB rates are higher, and declining more slowly, in individuals not native to the reporting countries compared with the native population. This highlights important health inequalities and major challenges to the control of TB, while it also illustrates difficulties in combining data from multiple countries.
Besides differences in the definition of TB cases of ‘foreign origin’ between countries, several points complicate interpretation of these data. Migrants constitute a heterogeneous group of individuals from multiple countries and with varying risk factor profiles, thus simply being ‘foreign born’ is not necessarily a good proxy for having a high risk of TB infection or disease, and particular risk factor profiles may be more common in some countries than in others, e.g. due to differences in migration patterns.
The implications of migration for TB incidence thus depend on detailed patterns of migration. There is therefore a need to further investigate, at country level, risk factors for TB in migrants and to further elucidate detailed migration and travel patterns and develop tailored solutions specific to the epidemic affecting each group.