The correct answer is Leon Calmette and Camille Guerin.Bacillus Calmette-Guerin (BCG) vaccine was developed by French bacteriologists Albert Calmette and Camille Guerin in 1921. It is used for the Prevention of Tuberculosis.The vaccine provides protection against meningitis, leprosy, non-invasive bladder cancers, and disseminated TB in children.A recent study has shown that the countries which have BCG vaccination in their immunization program have a low rate of death due to COVID-19.Tuberculosis (TB) disease is caused by Mycobacterium tuberculosis. Tuberculosis (TB) usually attacks the lungs.BCG vaccine was first considered by the WHO Expert Committee on Biological Standardization in its thirteenth report.BCG vaccine is one of the most widely used of all current vaccines.Additional InformationEdward Jenner - Edward Jenner, FRS FRCPE was a British physician and scientist who pioneered the concept of vaccines including creating the smallpox vaccine, the world's first ever vaccine. The terms vaccine and vaccination are derived from Variolae vaccinae, the term devised by Jenner to denote cowpox.Jonas Salk - Jonas Edward Salk was an American virologist and medical researcher who developed one of the first successful polio vaccines.Louis Pasteur - He pioneered the study of molecular asymmetry; discovered that microorganisms cause fermentation and disease; originated the process of pasteurization; saved the beer, wine, and silk industries in France; and developed vaccines against anthrax and rabies.