Tuberculosis (TB)

Infectious Disease

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Tuberculosis (TB) in humans is caused by a type of bacterium called Mycobacterium. There are different species of Mycobacterium, but the one which causes most cases of TB in humans is called Mycobacterium tuberculosis. 

TB is often thought of as an ‘old’ infectious disease that no longer affects people in the UK. Overall, there has been a downward trend in cases in the UK, but the rate of decline is slowing. 4,425 cases were reported in England in 2021. See the UKHSA TB incidence and epidemiology in England, 2021 for more information. 

Groups most at risk are people, and the families of people, from countries where there are high rates of TB (more than 40 cases of TB per year, for every 100,000 people), and people with social risk factors, such as homelessness, alcohol misuse or being in prison.

If TB is not treated it can be fatal, even in people with no other health issues. Around 350 people a year in the UK die from TB-related causes. The most severe forms of the disease are more likely to affect children.

TB usually affects the lungs, but it can affect almost any part of the body including bones and the nervous system. It can be treated by a long course of antibiotics, but TB which is resistant to the first line antibiotics is becoming more common, and some strains are resistant to almost all TB drugs (known as XDR strains).

 

TB can be very difficult to diagnose, especially in children. When TB affects the lungs, known as pulmonary TB, the main symptoms are a persistent cough lasting more than three weeks, and coughing up phlegm that may contain blood.

Other symptoms include chest pains, a high temperature, loss of appetite, weight loss, night sweats, and tiredness or weakness. TB can sometimes lead to meningitis, an infection that affects the brain and can be fatal. This is most common in children aged 0-4 years in areas with high rates of TB, and most common in adults in areas with low rates of TB.

Many people who are infected with TB develop a latent TB infection. This means the TB bacteria remain in the body, but the disease is inactive. People with latent TB do not show any symptoms and cannot pass the disease on to anyone else.

However, they are at risk of developing active TB at a later stage, especially if their immune system becomes weakened, for example, because of chemotherapy treatment, HIV infection, or old age. Latent TB develops into active TB in around 10% of cases but progression to disease is far more common in younger children.

 

TB is almost always passed on by tiny droplets coughed or sneezed into the air by an infected person. To catch TB, you usually need to be in close contact for a long time with someone who has TB, for example, people living in the same house. Less commonly, TB is passed on outside the home.

 

A vaccine against TB (the BCG vaccine) is available to protect groups who are particularly at risk of developing the disease. The vaccine is not currently offered to all children as part of the routine schedule in the UK except in areas with very high rates of disease.

A long course of antibiotics is also available to treat TB - usually a four-month or six-month course of antimicrobial drugs. Healthcare workers often provide support throughout treatment to make it easier for the patient to carry out the full course of their treatment. 

Since 2000, the World Health Organization estimates that 74 million lives were saved through TB diagnosis and treatment. 

 

TB Worldwide

TB is the main cause of death from an infectious disease that can be cured and prevented worldwide. The WHO estimates that in 2021, 10.6 million people became ill with TB - 6.7% of these cases were among people living with HIV. Worldwide, there were 1.6 million deaths from TB in 2021. 

In 2021, the largest number of new TB cases occurred in the WHO South-East Asian Region, with 46% of new cases. This was followed by the WHO African Region, with 23% of new cases and then WHO Western Pacific with 18%.

The WHO also estimates that about a quarter of the world’s population has latent TB, where the TB bacteria remain in the body, but the disease is not active. In 1993 WHO declared TB a global emergency, and its goal is to end the TB epidemic by 2030.

TB and HIV

TB is the leading cause of death for people living with HIV and causes one in five of all deaths in this group. This group of people are 16 times more likely to become ill from TB than people without HIV and have a 20 times higher risk of developing an active case of TB.

Out of the 1.6 million deaths from TB worldwide in 2021, 187,000 of these deaths occurred in people with HIV. 

 

 

Page last updated Wednesday, July 26, 2023