People who are most at risk include those with compromised immune systems, such as people living with HIV, malnutrition or diabetes, or people who use tobacco.
When a person develops active TB disease, the symptoms – cough, fever, night sweats, weight loss etc. – may be mild for many months. This poses a risk for others around them if the person is not diagnosed until the disease has progressed and symptoms have worsened.
People with active TB can infect 10-15 other people through close contact over the course of a year. Without proper treatment, 45% of HIV-negative people with TB on average and nearly all HIV-positive people with TB will die.