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WORLD HEALTH ORGANIZATION TECHNICAL REPORT SERIES. 1980; (651):1-19.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.
WHO Chronicle. 1980 Mar; 34(3):118-9.The World Health Organization (WHO) plan is to hold 2 meetings with tuberculosis experts for the purpose of examining the implications of a large scale trial in the south of India that has shown no protection against lung tuberculosis from BCG vaccination. Launched in 1971, the trial covered some 260,000 persons older than age 1 month. It was aimed at preventing lung tuberculosis in the population of 209 villages as well as in a town in the district of Chingleput, west of Madras. Results with the BCG vaccines have varied in the scientifically valid controlled studies that have been conducted. The success of BCG vaccines has varied by population group, ranging from good (80% effectiveness) to poor (as in the Indian trial). The following were among the questions raised by the findings of the Indian trial: were there procedural flaws; were the BCG vaccines used of adequate potency; could other factors have played a role; and should BCG vaccinations be stopped. According to the published report, there were no apparent flaws in the procedures followed in the Indian study. In the Indian trial, 2 BCG strains--Danish and French--were used in the highest tolerated doses. The strains were selected for their relatively high efficacy in experimental studies, and extensive laboratory control showed the vaccines to be of good quality. The WHO experts found the epidemiology of tuberculosis in the trial area to be peculiar in the sense that the tuberculosis occurred long after an individual was infected. Not far from the trial area, and also in south India, disease occurred soon after infection. The experts noted that this phenomenon, which requires further study, may influence the effectiveness of vaccination. According to the experts, the findings in the study population were not applicable in other parts of India. Where many factors may play a role and when the level of protection is nonexistent, as in the India trial, little can be deduced about the worth of the vaccine and its effect under different circumstances.