Vulnerable populations: risk factors and social determinants

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.