Tuberculosis

• 06 Sep 2021

Why in News

Centenary celebration is being observed for the Bacille Calmette-Guérin (BCG) vaccine, which is presently the sole vaccine available for the prevention of Tuberculosis (TB).

Key Points

• About:
  
  • TB is caused by a bacterium called Mycobacterium tuberculosis, belonging to the Mycobacteriaceae family consisting of about 200 members.
    
    • Some of Mycobacteria cause diseases like TB and Leprosy in humans and others infect a wide range of animals.
  • In humans, TB most commonly affects the lungs (pulmonary TB), but it can also affect other organs (extra-pulmonary TB).
  • TB is a very ancient disease and has been documented to have existed in Egypt as early as 3000 BC.
  • TB is a treatable and curable disease.
• Transmission:
  
  • TB is spread from person to person through the air. When people with lung TB cough, sneeze or spit, they propel the TB germs into the air.
• Symptoms:
  
  • Common symptoms of active lung TB are cough with sputum and blood at times, chest pains, weakness, weight loss, fever and night sweats.
• Global Impact of TB:
  
  • In 2019, 87% of new TB cases occurred in the 30 high TB burden countries.
  • Eight countries accounted for two thirds of the new TB cases:
    
    • India, Indonesia, China, Philippines, Pakistan, Nigeria, Bangladesh and South Africa.
    • India reported 1.8 million TB cases between January and December 2020 as compared to 2.4 million the year before.
  • In 2019, MDR-TB remained a public health crisis and a health security threat.
    
    • MultiDrug Resistant Tuberculosis (MDR-TB) is a strain of TB that cannot be treated with the two most powerful first-line treatment anti-TB drugs. Extensively Drug Resistant Tuberculosis (XDR-TB) is a form of TB caused by bacteria that are resistant to several of the most effective anti-TB drugs.
• BCG Vaccine:
  
  • BCG was developed by two Frenchmen, Albert Calmette and Camille Guerin, by modifying a strain of Mycobacterium bovis (that causes TB in cattle). It was first used in humans in 1921.
  • In India, BCG was first introduced in a limited scale in 1948 and became a part of the National TB Control Programme in 1962.
  • In addition to its primary use as a vaccine against TB, it protects against respiratory and bacterial infections of the newborns, and other mycobacterial diseases like Leprosy and Buruli’s ulcer.
  • It is also used as an immunotherapy agent in cancer of the urinary bladder and malignant melanoma.
  • One intriguing fact about BCG is that it works well in some geographic locations and not so well in others. Generally, the farther a country is from the equator, the higher is the efficiency.
    
    • It has a high efficacy in the UK, Norway, Sweden and Denmark; and little or no efficacy in countries on or near the equator like India, Kenya and Malawi, where the burden of TB is higher.
• Related Initiatives:
  
  • Global Efforts:
    
    • The WHO (World Health Organisation) has launched a joint initiative “Find. Treat. All. #EndTB” with the Global Fund and Stop TB Partnership.
    • WHO also releases the Global Tuberculosis Report.
  • India’s Efforts:
    
    • National Strategic Plan (NSP) for Tuberculosis Elimination (2017-2025), The Nikshay Ecosystem (National TB information system), Nikshay Poshan Yojana (NPY- financial support), TB Harega Desh Jeetega Campaign.
    • Currently, two vaccines VPM (Vaccine Projekt Management) 1002 and MIP (Mycobacterium Indicus Pranii) have been developed and identified for TB, and are under Phase-3 clinical trial.

Source: TH