RESUMO
The purpose of the present paper is to answer objections raised by some authors that conversion of Mitsuda negativity after BCG vaccination is caused by the antigenic action of the lepromin test previous to the vaccination. To this end there have been studied the effects upon the Mitsuda reaction of repeated lepromin injections, in comparison with the effects of orally administred BCG without previous lepromin test. Results obtained with 61 children of parents with leprosy are reported (2 children were lost from experiment, one by death and one by removal to another institution). These children, taken from their parents in their first dayof life, ranged in age at the beginning of the experiment from 3 days to 12 months 6 days. They were divided by lot into three groups so as to make the age relationship in each group approximatelythe same. Group A: 21 nonvaccinated children who underwent 4 lepromin test at intervals of about 3 months. After the fourth injection the Mitsuda reaction was positive in 9 cases (43%), only one of them strong enough to be necrotic. The 12 negatives were afterwards given BCG, and then 7 more (58% of the negatives) gave positive Mitsuda reactions. Group B: 20 children BCG-vaccinated orally with three weekly doses of 0.10 or 0.20 gm., according to age. a lepromin test performed nine months after vaccination gave 17 (85%) strongly positive (necrotic) Mitsuda reactions. The other 3 cases (one 1 + and two negative) were given another course of BCG vaccination, after which they were retested with lepromin; 2 of them then gave strongly positive (necrotic) Mitsuda reaction. Group C: 20 control children did not get BCG and were tested with lepromin for the first time 9 months after the study was begun. Al were completely negative. Analysis of the results from groups studied proved then to be statistcally significally significant, with...