A SPOTLIGHT ON TB – FRIDAY, MARCH 24, 2023
In 2023, the spotlight of World Tuberculosis Day will be on urging countries to ramp up progress in the lead-up to the 2023 UN High-Level Meeting on Tuberculosis. WHO will also issue a call to action with partners urging Member States to accelerate the rollout of the new WHO-recommended shorter all-oral treatment regimens for drug-resistant tuberculosis.
TB STATISTICS
Tuberculosis (TB) is the 13th leading cause of death worldwide and the second leading infectious killer after COVID-19 (above HIV/AIDS) with a total of 1.6 million deaths in 2021 (this includes 187000 people with HIV).
An estimated 10.6 million people fell ill with TB worldwide comprising 6 million adult men, 3.4 million adult women and 1.2 million children. Of these figures, WHO estimated that 304 000 individuals fell ill with TB (163 000 individuals with HIV) and 56 000 individuals died from TB (33 000 individuals with HIV)
Although TB is an entirely preventable and curable disease, it will continue to spread while the missing four million people remain undiagnosed and untreated. Finding them is essential if we are to end TB.
People are missed due to several reasons:
People with limited or no access to healthcare (diagnosis and treatment).
People who are not aware that treatment is available and accessible.
People are prevented from seeking treatment by the stigma surrounding the condition.
People with access to healthcare, but not identified as needing to be tested, or are tested but diagnosed incorrectly and treated.
People who are being treated for TB without being notified of national TB programs, such as informal care or some private care.
WHAT IS TB?
Tuberculosis (TB) is caused by bacteria called mycobacterium tuberculosis (M TB). TB disease -also known as Active TB or Pulmonary TB - is when TB bacteria become active and multiply in the body when the immune system cannot stop the bacteria from growing.
About a quarter of the global population is estimated to have been infected with M TB (also known as Latent TB Infection - LTBI). Individuals infected with LTBI have a 5% to 10% lifetime risk of falling ill with Active / Pulmonary TB Disease. Individuals with LTBI are not sick and cannot spread germs to others.
TUBERCULOSIS (TB) CHALLENGES
Individuals who have compromised immune systems, such as people living with HIV, malnutrition or diabetes, or people who use tobacco, have a higher risk of falling seriously ill with TB.
Without treatment, as with other opportunistic infections, HIV and TB can work together to shorten lifespan. Someone with untreated Latent TB Infection (LTBI) and HIV infection is much more likely to develop Active / Pulmonary TB Disease during his or her lifetime than someone without HIV infection.
Among people with Latent TB Infection (LTBI), HIV infection is the strongest known risk factor for progressing to Active / Pulmonary TB Disease. A person who has both HIV infection and Active / Pulmonary TB Disease has an AIDS-defining condition.
Child and adolescent TB is often overlooked because it can be difficult to diagnose and treat. One of the biggest challenges faced in children and adolescents is that the diagnosis of TB disease in HIV-infected children is the same as for HIV-uninfected children except that the diagnosis of TB is more complex because the symptoms and signs of TB and those of other HIV-related lung diseases could be indistinguishable. Symptoms such as chronic cough, weight loss and persistent fever are common in both HIV-related lung disease and Active / Pulmonary TB Disease.
Drug-resistant TB is one of the leading killers due to antimicrobial resistance, globally. WHO’s Global TB Report suggests that 3-4% of all TB cases diagnosed are resistant to multiple TB drugs (multidrug-resistant TB or MDR-TB) and, in some parts of the world, this proportion is much higher.
HOW IS TB SPREAD AND WHAT ARE THE SYMPTOMS?
Active / Pulmonary TB Disease, when it affects the lungs, spreads from one individual to another through the air. When individuals with lung TB cough, sneezes, or spit, they propel the TB germs into the air and if another individual inhales a few of these germs they can become infected.
When an individual develops Active / Pulmonary TB Disease the symptoms may be mild for many months which could lead to delays in seeking care and results in the transmission of the bacteria to others.
It is estimated that individuals with Active / Pulmonary TB Disease can infect 5 to 15 other individuals through close contact over X-ray one year. On average, without proper treatment, 45% of HIV-negative individuals with TB and nearly all HIV-positive individuals with TB will die.
Individuals with Latent TB Infection | Individuals with TB Disease (Active / Pulmonary TB) |
Has no symptoms | Individuals with TB Disease (Active / Pulmonary TB) Have symptoms that may include:
|
Does not feel sick | Usually feels sick |
Cannot spread TB bacteria to others | May spread TB bacteria to others |
Usually has a skin test or blood test result indicating TB infection | Usually has a skin test or blood test result indicating TB infection |
Has a normal chest x-ray and a negative sputum smear | May have an abnormal chest x-ray, or positive sputum smear or a culture |
Needs treatment for latent TB infection to prevent TB disease | Needs treatment to treat TB disease |
DIAGNOSING TB
There are several types of TB tests currently in the market used to diagnose or screen for TB, each with advantages and disadvantages.
Test Type | Test Time | Sensitivity & Specificity | Sampling Method | Test by Whom & Where |
OnSite TB IgG/IgM Combo Rapid Test | 15 minutes | Sensitivity - 87.2% Specificity - 94.6% | Whole blood | Basic skilled health care worker at any venue |
Chest X-ray | 15 - 30 minutes | The sensitivity and specificity vary between the radiographer and the radiologist/clinician reading the Xray. | X-Ray | Qualified Radiologist |
Gene Expert | 48 hours | More diagnostic and helps to differentiate sensitive from drug resistant TB. | Sputum test | Healthcare professional at a laboratory |
Tuberculin Skin Test or TST (Mantoux) | 72 hours | Sensitivity - 94% Specificity - 88% | Subcutaneous injection | Trained staff at hospitals or clinics |
QuantiFERON Gold / Igra test Interferon release gamma assay | 5 -7 days | Sensitivity - 93% Specificity - 95% | Whole blood | Healthcare professional at a laboratory |
TB Culture | 6 weeks | | Sputum or tissue | Healthcare professional at a laboratory |
TREATMENT
People infected with HIV who also have either Latent TB Infection or Active / Pulmonary TB Disease can be effectively treated. The first step is to ensure that people living with HIV are tested for TB infection. If found to have TB infection, further tests are needed to rule out TB disease. The next step is to start treatment for Latent TB infection or Active / Pulmonary TB Disease based on test results.
TB Treatment Success
WHO data has suggested that 86% of patients with drug-sensitive forms of TB are treated successfully. However, many “successfully treated” individuals are left with scars from their TB illness, both physical such as chronic lung disease, and psychological, which includes anxiety or mood swings. In response to this, the International Union against TB and Lung Disease have published a set of standards for the clinical management of patients who suffer from post-TB lung disease.
More and more research identifying damaging immune responses to TB bacteria has highlighted treatment for potential candidates to improve long-term outcomes from TB, pending further clinical trials.
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