Vaccination against tuberculosis. Report of an ICMR/WHO Scientific Group.
This document reports the discussions of a Scientific Group on Vaccination Against Tuberculosis, cosponsored by the Indian Council of Medical Research and the World Health Organization (WHO), that met in 1980. The objectives of the meeting were to review research on Bacillus Calmete-Guerin (BCG) vaccination, assess the present state of knowledge, and determine how to advance this knowledge. Particular emphasis is placed in this document on the trial of BCG vaccines in South India. In this trial, the tuberculin sensitivity induced by BCG vaccination was highly satisfactory at 2 1/2 months but had waned sharply by 2 1/2 years and the 7 1/2-year follow up revealed a high incidence of tuberculous infection in the study population. It is suggested that the protective effect of BCG may depend on epidemiologic, environmental, and immunologic factors affecting both the host and the infective agent. Studies to test certain hypotheses (e.g., the immune response of the study population was unusual, the vaccines were inadequate, the south Indian variant of M tuberculosis acted as an attenuating immunizing agent, and mycobacteria other than M tuberculosis may have partially immunized the study population) are recommended. A detailed analysis should be made when results from the 10-year follow up of the south Indian study population are available.