[Antitubercular chemoprophylaxis after 20 years of its world-wide application].

The researches carried out on calves (1952--1953) and over 3000 guinea-pigs, rabbits and rats in the Forlanini Institute of Rome for five years, are remembered. The first clinical experiment on a group of 500 children exposed to family contagion (1955--1956) is also related. The links between INH-prophylaxis and anti-tuberculous immunity, and between INH-prophylaxis and vaccination with BCG are discussed.