Do Tuberculosis Screening Programs Hold the Key to Prevention?
What is the TB screening program?
Tuberculosis is a chronic infectious disease that can cause millions of deaths worldwide. Even though tuberculosis is a curable disease, people who are affected by the latent infection are unaware of it due to the silence it maintains throughout the phase of infection. This leads to difficulty in getting proper treatment, which can be fatal over a period of time. The lack of awareness about the screening programs and the asymptomatic infection can increase the risk of TB and its mortality rate. Today, we are going to discuss the various screening programs that are available to prevent TB infection.
What is TB and its prevalence?
It is an infection caused by Mycobacterium tuberculosis, primarily affecting the lungs. It is a chronic disease spread through airborne particles when an infected individual coughs, sneezes, or spits.
TB disease and latent TB infection are the two tuberculosis conditions. Tuberculosis disease is an active form of contagious microbial infection that can cause symptoms in individuals. However, people with latent TB infection cannot experience any symptoms and have not spread to others. This can gradually develop into TB disease over a period of time.
TB is the second leading death-causing infection in individuals. The World Health Organization (WHO) has estimated that over 1.3 million people died from tuberculosis, and about 10.6 million people were infected in the year 2022. It is estimated that India accounts for 25% of the global TB population, and over 2.77 million people were affected by TB in the year 2022.
How Does Tuberculosis Screening Work?
Tuberculosis screening can help prevent and treat the spread of disease in individuals and the community. It is crucial to plan a screening program to identify asymptomatic latent tuberculosis infection in individuals before it spreads into TB disease. Here are the tuberculosis screening procedures that everyone needs to know and plan in the TB prevention process.
What is the Tuberculin Skin Test (TST)?
The tuberculin skin test, or Mantoux, is a simple and safe TB test procedure that involves the intradermal administration of 0.1 ml of tuberculin-purified protein derivative (PPD). After 48 and 72 hours, your healthcare provider can assess the skin for a pale elevation, known as an induration. A diameter of 10mm of the elevated induration indicates an increased risk of TB in individuals, while a diameter of 15mm indicates a lack of risk factors for TB.
Benefits:
- It applies to children who are younger than five years of age.
- It applies to people like doctors or healthcare professionals who need repeated testing annually.
- It is a cost-efficient and simple test.
Limitations:
- This test can only assess the Latent tuberculosis infection LTBI and is not recommended for detecting active TB disease.
- The sensitivity of the TST is only 70–85%, which may give false positives (give a positive result for a person who does not have TB infection) or false negatives (give a negative result even though that person is affected by LTBI) results in individuals.
- Due to its lower sensitivity to TB, it cannot differentiate between TB and LTBI in individuals.
What Are Interferon Gamma Release Assays (IGRAs)?
The United States Food and Drug Administration and WHO have approved two IGRAs for detecting tuberculosis infection. The QFT-plus and T-Spot tests have helped detect tuberculosis with a slightly increased specificity compared to TST.
QFT-Plus test: The QFT-plus is a form of ELISA-based test (enzyme-linked immunosorbent assay) that can measure the released Interferon gamma (IFN-γ) in the samples. However, due to its cost-effectiveness, it is no longer available commercially.
T-Spot test: This is an enzyme-linked immunospot assay that involves collecting blood cells from the patient to detect the TB infection. It helps to detect the T-cell effect against Mycobacterium tuberculosis in the patient's blood sample.
Benefits:
- It is a time-saving procedure that needs only a single visit to the patient.
- You can get the result within 24 hours.
- It does not cause false positive results.
- It is more accurate than TST.
Limitations:
- It may be quite expensive when compared to the TST.
- Limited data are available for the application of IGRA in children under five years of age and persons who have had recent exposure to M. tuberculosis.
- The samples need to be processed within 8-30 hours after collection.
Who Needs To Get A Tuberculosis Screening?
1. If you are spending time with a TB-infected person.
2. If you belong to a prevalent country like Latin America, the Caribbean, Africa, Asia, Eastern Europe, or Russia.
3. If you are living or working in a place with a high risk of infection (nursing homes or homeless shelters).
4. If you are a healthcare worker taking care of TB-infected patients,
5. If you are an HIV-affected individual.
6. If you have had a TB infection in the last two years.
7. If you come under small age groups.
8. If you are a person using drugs (illegally).
9. If you have an immune disorder.
10. If you are an older adult.
Tips For Preventing Tuberculosis Infection
- Avoid contact with a TB-infected person.
- Wear a mask that properly covers your mouth and nose.
- Get a BCG vaccine if you are living or traveling in a TB-prevalent area.
- Wash your hands before and after sneezing or coughing.
- Wear proper Personal Protective Equipment if you are working in the healthcare sector.
- Plan for tuberculosis test programs to avoid the spread of LTBI.
End-Notes
Tuberculosis can be easily prevented and cured if it is diagnosed in the early phase. LTBI, like a silent killer, needs regular screening plans to prevent the spread of the disease before it turns into a chronic tuberculosis disease. The lack of awareness about the early detection and screening program can increase the mortality rate for TB. The stigma of TB can be removed by taking proactive steps like regular screening programs and spreading awareness about the importance of TB screening in our community. Let’s spread the importance of TB screening and protect our loved ones from the risk of TB.
