In all, 1,259 students aged 11-19 years from three boys high school of Bangalore, formed the study group. They were tuberculin tested with 1 TU RT 23 containing Tween 80. Boys with a reaction of 13 mm or less to tuberculin test and willing for BCG vaccination were allocated in 3 groups: (i) to be vaccinated with Madras vaccine (211), (ii) to be vaccinated with Danish Vaccine (236), (iii) control with saline injection (231) (placebo). Strength of Madras and Danish vaccines used was same, 0.075 mg per dose. After 3 months of vaccination, second tuberculin test with 1 TU RT 23 with Tween 80 was given to 575 boys included in both the vaccinated groups and in the control group. A follow up at one year after vaccination was done among 328 boys, who were again tuberculin tested.

The analysis of data shows that the mean size of post-vaccination tuberculin test induration among Madras BCG vaccinated group was 11.8 mm and among Danish BCG vaccinated group, it was 11.9 mm, the standard deviation were 3.8 and 4.5 mm respectively. The above differences between the 2 vaccinated groups were not-statistically significant. Similarly, the post-vaccination allergy in the two BCG vaccinated groups at the end of one year was not-significantly different. The mean size of the scar produced by two vaccines were also smaller. The post-vaccination allergy among persons whose pre-vaccination tuberculin induration was 9 mm or more to 1 TU RT 23 with Tween 80, did not increase by more than 4 mm after vaccination. While the group whose pre-vaccination tuberculin induration was below 9 mm, had an increase of post-vaccination allergy of a little over 8 mm. It is concluded that the allergy producing capacity of the Danish and Madras vaccines was not different.