AbstractPneumococcal pneumonia continues to be an important disease in terms of prevalence, morbidity and mortality. With the discovery of penicillin and its wide clinical use, the overall mortality of pneumococcal pneumonia has been significantly reduced, but problems remain. These include: 1) death rate is uninfluenced by the antibiotic in the first five days of illness; 2) death rate in certain high risk groups and in patients infectecd with type 3 pneumococcus exceeds 25%; and 3) penicillin resistant strains of pneumococci have emerged. Because of these and other considerations, a modern 14-valent pneumococcal vaccine has been developed by Robert Austrian and his co-workers. The vaccine has been found to be immunogenic and effective in a number of populations studied. Additional efficacy studies are needed, however, particularly in certain high risk groups, such as the elderly and immunocompromised patients.