The present invention relates to the use of an immunotherapeutic agent comprising cell wall fragments of a virulent strain of Mycobacterium tuberculosis for the preparation of a drug suitable for the primary prophylaxis of tuberculosis. The immunotherapeutic agent is capable of inducing a protective response that is more effective than the conventional BCG vaccine and reduces the number of viable bacilli in the lungs and in the spleen of individuals recently infected by M tuberculosis.
