The Government of India and the Government of Bengal are both eager to introduce Bacillus Calmette-Guerin (B.C.G.) Vaccination on a large scale in order to prevent the high incidence of tuberculosis which has been spreading rapidly throughout the country. A batch of experts have been sent by the World Health Organisation to popularise the B.C.G. Vaccination and to demonstrate to the authorities concerned the process of manufacture of the vaccine and they have taught local workers, the technique of its administration.
Since many years research workers have been trying to invent a serum or vaccine for the prevention of tuberculosis. Professor Calmette and his collaborator Guerin have given us this B.C.G. Vaccine, by working on the principles invented by the great German scientist Koch. Koch in 1894 made an experiment by injecting tubercle bacilli under the skin of a healthy guinea pig. Within two weeks he noticed swelling of the glands near the site of the injection as also the wound remained open and continued to discharge pus until the death of the animal.
But when he repeated the same experiment on a tuberculosis guinea pig, the wound soon healed up and the nearest glands were also not inflamed. Before Koch the French Doctor and Scientist Marfan showed in 1886 that when a person was recovering from an infectious disease he develops in his system a resistance to further infection which cannot produce the disease again. This observation of Marfan has in fact the origin of the principle of immunization. Calmette and Guerin in 1907 used Kochs experiment for preparing a vaccine against tuberculosis.
Kochs tuberculin even in very small dose proved dangerous. So Calmette and Guerin tried to invent a process by which the bacilli would lose their virulence and would be incapable of producing tuberculosis even in the most susceptible animal like the guinea pig. By their labour extending over a period of 13 years, a “live” vaccine was prepared from a special strain of tubercle bacilli which was so attenuated that it had lost its capacity to produce the disease and it is claimed that the inoculation of these bacilli in healthy animals did no harm to them.
The Government wants to use extensively the B.C.G. Vaccine for the purpose of creating immunity against tuberculosis amongst its people. There is one very important condition for its use; that the persons who are to be injected with this vaccine must be conclusively proved to have no infection beforehand. “The Norwegian Association for the prevention of Tuberculosis advocates the B.C.G. Vaccine for healthy persons who are exposed to infection and young tuberculin negative members of tuberculous families.
The method of carrying out Vaccination is of the utmost importance. Not the slightest mistake must be made. There are two important rules (1) The child must be given the vaccine three times in the first ten days after birth (2) For the following six to eight weeks it must be kept away from all possible sources of infection.” (Dr. M. Sekulich).
It is clear that the conditions for the use of the vaccine are not so easy. Even the healthy subjects after the inoculation, are probably made more sensitive to fresh infection, as immunization and sensitization are two simultaneous processes, and as such it cannot be strongly denied that the live vaccine (B.C.G.), although claimed to be much less potent, can become active under circumstances contravening the strict adherence to the conditions laid down.
In fact the injunction of keeping the inoculated person away from possible source of infection for some length of time, is a precaution against the sensitized condition of the subject. But it must be admitted that it is very difficult, if not impossible, to observe such a condition, as any gust of wind can carry the infection, so widely existing in the atmosphere and over which no body has got any control whatsoever.
Although the use of the vaccine is extensively prevalent in the continent of Europe, it is not so much favoured in England. In this connection I would like to quote the opinion of Dr. F. W. Price from the “Text Book of Practice of Medicine”, in respect of the use of the B.C.G. vaccine, “It is too early to assess the results, but there is one great objection to the method, that is, the possibility that the organism itself may be capable of regaining virulence in the human body”.
I would also like to quote Dr. G.S. Erwin of England from his Book, “A Guide for the tuberculous patient”; “Inoccupation of the dead germ of tuberculosis or its products (tuberculin) has not met with any success, but better results are claimed for the second method. By various culture methods strains of the tubercle bacillus relatively harmless to man can be produced in the laboratory.