What is the Bacillus Calmette–Guérin (BCG) Vaccine?

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What is the Bacillus Calmette–Guérin (BCG) Vaccine? Blog Image


The BCG vaccine, typically administered to prevent tuberculosis, did not provide any significant protection against Covid-19 infection to healthcare workers, a new study said.

About Bacillus Calmette–Guérin (BCG) Vaccine:

  • It is a vaccine for tuberculosis (TB) disease. 
  • The vaccine was developed by Calmette and Guerin and was first administered to human beings in 1921.
  • It is the most widely administered vaccine and is usually a part of the routine newborn immunization schedule.
  • BCG vaccine also offers protection against non-tuberculous mycobacterial infections like leprosy and Buruli ulcer.
  • It is often given to infants and small children.
  • It is rarely given to anyone over the age of 16 because there is little evidence it works very well in adults.

Key facts about Tuberculosis (TB):

  • Tuberculosis (TB) is caused by bacteria (Mycobacterium tuberculosis)that most often affect the lungs.
  • It is curable and preventable disease.
  • Two kinds of tuberculosis infection:
    • Latent TB- The bacteria remain in the body in an inactive state. They cause no symptoms and are not contagious, but they can become active.
    • Active TB - The bacteria do cause symptoms and can be transmitted to others. About one-quarter of the world's population has latent TB.
  • People infected with TB bacteria have a 5–15% lifetime risk of falling ill with TB.
  • However, persons with compromised immune systems, such as people living with HIV, malnutrition or diabetes, or people who use tobacco, have a much higher risk of falling ill.
  • 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.
    • Even after inhaling a few drops of these germ, a person can get infected.


Q1) What is leprosy?

Leprosy is a chronic infectious disease caused by a type of bacteria, Mycobacterium leprae. The disease predominantly affects the skin and peripheral nerves. Left untreated, the disease may cause progressive and permanent disabilities.

Source: Why It Matters | Does the BCG vaccine prevent Covid-19? No, says study.