Tuberculosis (TB) is the result of the interaction between the TB bacilli and the body’s immune system. In the WHO European Region, 1 in 7 people are infected by TB, but are not ill with the disease – this is called a latent TB infection (LTBI). Up to 10% of people with LTBI develop TB disease at some time in their lives. High exposure to the TB bacilli and/or lower immune defences increase vulnerability and therefore the chances of developing the disease.
LTBI management requires specific guidance and is particularly relevant to sustaining the TB elimination phase in countries with low and intermediate TB incidence. WHO is developing evidence-based guidance to support countries in the European Region to improve LTBI management.
Risk factors and social determinants
Risk factors increasing the exposure to the TB bacilli include crowding and poor ventilation in environments with a person with infectious TB. The most common risk factors that decrease immune defences include tobacco smoke and other types of air pollutants, HIV infection, malnutrition, alcoholism, diabetes, silicosis and immuno-depressive treatments, such as chemotherapy.
Multisectoral action on the determinants of health can greatly benefit TB care and prevention through social, economic and public health policies that:
- pursue overarching poverty reduction strategies and expand social protection;
- reduce food insecurity;
- improve living and working conditions;
- improve environment and living conditions in prisons and other congregate settings;
- address the social, financial and health situation of migrants;
- promote healthy diets and lifestyles, including reduction of smoking and harmful use of alcohol and drugs.
Vulnerable populations
Prisoners, migrants and socially marginalized people are particularly vulnerable because of the increased exposure associated with their living conditions. People living with HIV or suffering from other conditions that weaken the immune system, such as diabetes, are especially vulnerable because this greatly increases their risk of developing the disease. Children are also vulnerable because of their weaker immune systems.
TB and migration
While usually fit to travel, migrants may have a higher risk of becoming infected or developing tuberculosis (TB) depending on: the TB incidence in their country of origin; the conditions experienced during their travel (physical stress and contact with infectious cases in camps and prisons); and their living and working conditions in the country of immigration, including access to health services and social protection. The active disease occurs in only a proportion of those infected and in half of the cases 5 years after immigration.
TB is very rarely transmitted from migrants to the resident population due to its low infectiousness and the limited social mixing of the two populations.
In consideration of the higher risk of TB for migrants, it is important to carry out tailored TB screening aimed at early detection and treatment of TB infection and disease. TB must, however, never be used as a reason to limit access to uninterrupted treatment through deportation. The continuum of care must be ensured at all levels and through appropriate cross-border communication and follow-up.
Minimum package of cross-border TB control and care interventions
Universal health coverage should be ensured for refugees and migrants, both documented and undocumented. The WHO European Region is the only one in the world with a consensus document on the minimum package of cross-border TB control and care interventions. These include ensuring access to medical services, irrespective of a migrant's registration status, and a non-deportation policy until intensive TB treatment has been completed.
As part of the implementation of the package, an online platform supports cross-border management of TB cases by facilitating communications among clinicians from different countries (in terms of sharing information for clinical management and contact tracing and referral of patients). This platform was made available as an additional function of the TB Consilium, established through a collaboration between WHO/Europe and the European Respiratory Society.
TB in prisons
In the WHO European Region, tuberculosis (TB) remains a major infectious disease in the prison system, especially in eastern Europe. Prisons are considered reservoirs facilitating TB and multidrug-resistant TB (MDR-TB) transmission within their walls, as well as to the community at large. Transmission occurs through prison staff, visitors and released inmates.
Prison system challenges to TB control
- Prisoners come from high-risk groups of the population and are in general poor, have little education and come from socioeconomically deprived sectors of the population, where TB infection and transmission are higher. They have often had limited access to health care and suffer from additional health problems such as alcoholism, tobacco smoke, drug addiction and HIV.
- Prisons have high exposure to TB, because of factors that cause infection and progression of the disease. These include overcrowding; poor ventilation; frequent transfer of prisoners between prisons; poor infection control practices; poor nutrition; limited access to health care, with delays in diagnosis (due to insufficient laboratory capacity and diagnostic tools); and inadequate treatment (e.g. interrupted supply of medicines).
As a result, notified TB cases in European prisons are, on average, 17 times higher than in the general population – ranging from 11 times higher in western Europe to 81 times higher in eastern Europe.
Improving TB control in prisons
Improvements can only be achieved with governmental commitment, interventions equivalent to those in the civilian system and in close collaboration with it, and partnerships with civil society organizations.