Six hundred and sixty four children attending elementary schools in and around the town of Butajira in Shoa district of Ethiopia have been skin-tested with a sonicate tuberculin and the responses have been divided into two different types. One of these types is believed to indicate protective immunity and the other tissue damaging hypersensitivity. On the basis of these responses previously administered BCG vaccination has been assessed for its protective efficacy which, it is suggested, is above 80%. This system of assessment also indicated that school entry age would be a very suitable time for BCG vaccination in the region. If the system can be established as useful, its potential value in planning BCG campaigns in developing countries is considerable.
Adolescent Adult