Tuberculosis (TB)

TB facts and figures

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Days

The average case of TB requires 180 days of medications, in addition to x-rays, labs, follow-ups and testing of contacts 18

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Global cost of reducing TB deaths

Wiping out TB by 2045 would cost up to $10bn per year1

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People became sick with TB

In 2019, 5.6 million men, 3.2 million women and 1.2 million children became sick with TB1

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Cases of drug resistant TB

In 2019, an estimated 484,000 people developed drug resistant TB, which is harder to treat1


Signs and symptoms

TB bacteria are most commonly found in the lungs. They can, however, spread to other parts of the body, in which case the symptoms would be localised in those areas. LTBI has no symptoms. Common symptoms of TB disease in the lungs include19:

  • A bad cough that lasts 3 weeks or longer
  • Pain in the chest
  • Coughing up blood or sputum (phlegm from deep inside the lungs)
  • Weakness or fatigue
  • Weight loss
  • Loss of appetite
  • Chills
  • Fever
  • Night sweats

Transmission

Exposure to TB occurs when you have spent time with someone who is infected with active TB disease. The bacteria are spread through the air when a person who has active TB sneezes, coughs or speaks. If you think you have been exposed to active TB, you should immediately contact your doctor or the local public health department20.

Risk factors

Learning about TB and the risk factors for TB is important, as there are several different factors that can make a person susceptible to TB. However, these risk factors usually fall into two categories21:

  1. Being in close contact with someone who has been recently infected with TB
  2. Having a medical condition that weakens the immune system

1. Close proximity

The chances of a person getting infected with TB are higher for people that are in close contact with others who are infected. This includes21:

  • Family and friends of a person with TB
  • People who come from areas of the world with high TB rates
  • People in groups with high rates of TB transmission – such as the homeless, injection drug users or a person with HIV
  • People who work or reside in a place where the people are at a high-risk for TB – such as hospitals, homeless shelters, correctional facilities or nursing homes

2. Weak immune system

People who have a weak immune system are at a high-risk for developing active TB. These include21:

  • Babies and young children
  • People with chronic diseases
  • People with HIV/AIDS
  • Organ transplant recipients
  • Cancer patients undergoing chemotherapy
  • People receiving certain specialised treatment for autoimmune diseases

Overall, 5-10% of people with latent TB who don’t receive treatment will develop active TB disease at some point in their lives.1

Testing

There are two categories of commercially available tests to detect TB infection:

Tuberculin skin test (TST)

The TST has been used to detect TB infection for over 100 years. It requires an intradermal injection of a small amount of purified protein derivative (PPD), a TB antigen, into the skin. In 48 – 72 hours, the resultant induration is measured22.

Process:

  • Tuberculin is injected into the skin on the lower part of the arm
  • Subject returns 48 to 72 hours later to have their test “read” to determine whether there has been a reaction to the tuberculin

Limitations:

  • Limited sensitivity, especially in the immunocompromised, young and elderly
  • Poor specificity; caused by:
    • Prior bacille Calmette–Guérin (BCG) vaccination
    • Non-tuberculosis mycobacteria (NTM) infection
  • Requires 2 visits
    • Failure to return for second visit = no test result
  • Subjective result
    • Administration and interpretation steps are technique-dependent  

Interferon-gamma release assays (IGRAs)

Three IGRAs currently approved by the FDA for use as an aid in diagnosing TB are: the T-SPOT.TB test, the multi-tube ELISA test and the Chemiluminescence immunoassay (CLIA). These tests each involve a blood draw, which is then processed by a lab.

Treatment

People with active TB disease must be treated and must take all of their medication exactly as directed. If they do not do this, the TB bacteria can become resistant to the drugs used to treat it. A typical course of treatment for active TB lasts from 6 – 9 months23.

It is is important to remember that TB is contagious and can be spread by an infected person coughing. For this reason, TB treatment often involves a period of isolation.

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