Brazilian experience with oral B.C.G.

Abstract

Summary I am emphasizing the high protective value of the oral B.C.G. method used in Brazil, which is based particularly in (1) a special strain—Moreau; (2) young cultures; (3) high dosage (100 to 200 mg.); (4) repeated doses, “concurrent vaccination” — monthly, fortnightly, weekly, or even bi-weekly, totaling 600 mg. to 4 Gm. Tuberculin positivity, produced by a a single dose of oral B.C.G. or by a previous virulent infection, becomes weaker or even negative, after repeated oral B.C.G. This tuberculin desensitization, according to the experience of Brazilian investigators, means, as a matter of fact, a bacterial disallergization, since it coincides with higher immunity. Lepromin-positive tests (Mitsuda), produced by a single dose of oral B.C.G., on the contrary, become stronger when repeated doses are given. At present, studies are being conducted on the immunizing value of the positive lepromin test induced by B.C.G. The Brazilian experience with oral B.C.G. has proved the safety of mass vaccination of the population, without previous tuberculin tests or roentgenograms, in the campaign against tuberculosis and, perhaps, leprosy.