Trial of an oral bacterial antigen against common colds.

Some of the discomfort and catarrh following colds may be due to bacterial infection ofthe mucous membranes damaged by viruses. It has been shown that autologous vaccines given parenterally can in fact reduce the duration of colds (Ritchie, 1958; Miller, McDonald, Williams, and Wilson, 1960) although standard mixed catarrhal vaccines had no such effect (Diehl, Baker, and Cowan, 1940). The use of oral mixed bacterial antigens has in the past seemed intrinsically unlikely to succeed but has been investigated in this study for two reasons. Firstly, the discovery of the IgA local secretory antibody system (Tomasi, Tan, Solomon, and Prendergast, 1965) and its relevance to respiratory virus infections (Rossen, Kasel, and Couch, 1971) made it seem possible that a locally administered vaccine might achieve results which others did not and, secondly, a double-blind trial had shown an apparently statistically significant reduction in the number of colds occurring in a group of students who were given an oral antigen at the beginning of winter (Newbold and Savage, 1971).