Who is at risk of TB?

People are most at risk from tuberculosis if they know someone who already has, or has had, TB. This could be someone they live or work with, or a close friend. It usually takes eight hours or more exposure for enough TB bacteria to build up in the body to be a risk.
Zambian mother and child at home
Anyone can be affected by TB, though certain factors do increase risk. These are common to low-incidence countries like the UK as well as high-incidence regions such as Africa and Asia.

  • Living where TB is common: You are more likely to be exposed to TB bacteria if you live in an area where TB is common. TB tends to cluster in urban areas – London has over 40% of the UK’s TB cases. Worldwide, just 22 of countries have more than 80% of the world’s TB cases.
  • Homelessness, or living in poorly ventilated or overcrowded accommodation: TB bacteria can spread more easily and remain suspended in the air for longer in poor housing conditions or working environments.
  • Immune system pressures: poor nutrition, poverty, poor housing and substance misuse can all weaken the immune system. Other illnesses can also make someone more vulnerable to TB. People living with HIV are at a particular risk from TB.

Find out more about the social and economic factors that can make people more vulnerable to TB, by going to Global TB challenges.