Antituberculous Chemoprophylaxis with Isoniazid Preliminary Note

¹ Director, Carlo Forlanini Institute and Professor, Rome University.

1. The author starts with the assumption that at the present moment, in the antituberculosis fight in Italy, it is necessary—at least for the length of one generation—to perform specific prophylaxis in addition to non-specific prophylaxis. This gives rise to the problem: antituberculous vaccination or chemoprophylaxis? The author favors the second course of action and especially the institution of chemoprophylaxis using high doses of isoniazid (20 mgr./Kg. daily) in skin-positive infants and children if living in tuberculous households. He reports and analyzes various experiments carried out in the United States and at the Forlanini Institute of Rome, and experiments carried out on calves by workers at Perugia University which uniformly prove that isoniazid administered under proper conditions is able to protect subjects from a massive infection and to confer upon them an increase of resistance against the tubercle bacilli comparable to that by means of vaccination with BCG.

2. The author feels that there is sufficient experimental basis for utilizing this system of prophylaxis in man. He has widely publicized the investigations going on in Rome, pointing out the excellent tolerance to the drug, even though given for a long period and in high doses to children, and the practical possibility of instituting a program of prophylaxis with isoniazid in cases of tuberculin positive individuals who do not have clinically detectable tuberculosis. This experiment in man (which, in addition to that announced by Debre in Paris, is the first in world medical literature) to date deals with 600 children under treatment for a period of six months while living either at home with tuberculous relatives or in preventoria and antituberculosis colonies. The drug was administered in the dosage of 20 mgr./Kg. daily in the form of lozenges, syrups, jello, chocolates, or isoniazid biscuits, and was perfectly tolerated.

3. The author discusses Canetti's proposal of combining chemoprophylaxis with vaccination using for the latter a BCG strain, INH-resistant and catalase-positive. He concludes that such a program would be difficult to put in practice and would carry with it a certain danger. A tentative scheme of treatment with INH for prophylactic purpose is proposed according to whether the skin-positive children involved are in a contagious or non-contagious environment. Finally, the author believes that a program could also be applied in the fight against bovine tuberculosis, thus protecting calves living in infected stables, adhering fundamentally to the regimen utilized in man with variations normally imposed by the difference of species and environment.