Of postulates and peccadilloes: Robert Koch and vaccine (tuberculin) therapy for tuberculosis.

In August 1890, Robert Koch dramatically announced that he had discovered a cure for tuberculosis, and the world rejoiced. The miracle substance was subsequently revealed to be tuberculin, inoculated as a 'vaccine therapy'. However, within a matter of months his claims were disputed and debunked, and his reputation was grievously damaged. The nationalistic pressures, professional jealousies and pecuniary interests that drove Koch's premature announcement are reviewed here and discussed in a context relevant to the development of therapeutic vaccines for human immunodeficiency virus infections.