- JAPANESE SOCIETY FOR TUBERCULOSIS
- 結核 (ISSN:00229776)
- vol.62, no.2, pp.51-60, 1987-02-15 (Released:2011-05-24)
BCG vaccination against tuberculosis has been carried out for more than half century since the birth of BCG vaccine. The progress and problems of BCG vaccination in the world were briefly reviewed here in two aspects, protective effectiveness and complications, especially during recent 10 years.1. General status of BCG vaccination todayIn most countries, intradermal injection with freeze-dried BCG vaccine is being performed in young children, particularly new-borns and infants in developing countries. Percutaneous BCG vaccination, now being conducted in a few countries, has less complications but varied effectiveness. The BCG strain, dosage and viability of the vaccine have carefully been selected in each country, especially for young children, as these factors were found to be closely related to the effectiveness and complications of the BCG vaccination.2. Effectiveness of BCG vaccinationIt is surprising that the efficacy of BCG vaccination has extensively been disputed up to the present, because the most reliable controlled trials carried out since 1930, had shown very much disparate results of protective effectiveness from none to some 80 %. A well-designed large-scale controlled trial with the secured freeze-dried BCG vaccine was carried out recently in South Indian in order to verify the efficacy of BCG vaccination. However, the South Indian trial gave no protection against bacillary pulmonary tuberculosis in children and young adult throughout 15 years of follow up.Explanations and hypothesis have been proposed so far for the unexpected results of the South Indian trial, and vaccine dose (viability), infectious with atypical mycobacteria and weak pathogenicity of infectious tubercle bacilli in local area were taken up for the possible causes. Although until present any hypothesis has not yet been confirmed, it can be said that the BCG vaccination may not always be effective in some area of the world.As the South Indian trial gave no direct information on the efficacy of BCG vaccine in child hood type tuberculosis, a policy to continue BCG vaccinaion in young children was recommended. Also a number of the retrospective studies had shown the protective effect of BCG vaccine against childhood tuberculosis. However, the controlled BCG trial in infants was desired in the future and recently the case-control study in children was carried out to prove the efficacy of BCG vaccination in tuberculosis contacts.3. The complications of BCG vaccinationThe BCG vaccine should be highly effective with less complications. However, the stronger the BCG strain used the more the complications in terms of the suppurative lymphadenitis in young children, as shown in the comparison of vaccine strains between French and J apanese in the field study. As a result, the vaccine of stronger strain which may be more immunogenic, had to be adjusted in the dosage to expect acceptable complications.More serious complications such as disseminated BCG infectious had never been systematically determined on a world-wide scale. On behalf of IUAT, A. Lotte et al had the first time systematically calculated the incidence of serious complications of BCG vaccinaion on a world scale. The number of disseminated BCG infectious (non-fatal and fatal) and post-BCG diseases were disclosed in the comprehensive study. Although the incidence of the serious BCG complications was extremely low, this survey is very useful for decision of BCG vaccination policy in the future along with the protective effectiveness of BCG vaccination in the area.