A twenty-year appraisal of BCG vaccination in the control of tuberculosis.

Few topics in the field of tuberculosis have engendered such divergent opinions as has the use of BCG vaccination in the control of tuberculosis. The views held by the medical profession in the United States on this subject have been either adversely critical, enthusiastic, or skeptical. Unfortunately, some of the unfavorable views have been expressed by those who have had no firsthand experience in this field and whose opinions have been often based on selected reports rather than on a critical review of the available literature. On the other hand, there was little justification for the enthusiasm of some advocates, based as it was on the results either of uncontrolled studies or of studies which were open to criticism. Although the introduction of antimicrobial agents ushered in a new era in the treatment of tuberculosis, the prophylactic value of these agents for man remains to be proved. Foci of tuberculous