Problems and progress towards vaccination against bacterial infections of the respiratory tract.

A large number of bacterial species are causative agents of respiratory tract disease. The discussion will center on three infections selected because they represent different problems in control on the basis of epidemiologic and immunochemical factors. Group A hemolytic streptococci are common upper respiratory tract pathogens which may initiate severe non-suppurative sequelae such as rheumatic fever and glomerulonephritis. Recent progress concerning M protein vaccines will be reviewed. Pneumococci are still the most frequent cause of pneumonia at all ages. Pneumococcal vaccines are the prototype for purified polysaccharide vaccines since their effectiveness was demonstrated 30 years ago. The major problem in vaccination is the very large number of capsular serotypes. Pseudomonas aeruginosa represents the relatively new problem of gram-negative bacterial infections in the immunodepressed host. Demonstration of seven immunotypes as the cause of 90% of human infections has led to preparation of a multivalent vaccine composed of lipopolysaccharide antigens. Current knowledge of this vaccine will be discussed.