Comparing potential benefits of new pneumococcal vaccines with the current polysaccharide vaccine in the elderly

We compared the hypothetical effects of the 23-valent polysaccharide pneumococcal vaccine with new vaccines on preventing invasive and noninvasive pneumococcal disease in persons greater than or equal to65 years. We estimated how much disease would occur if no polysaccharide vaccine were in use and used this baseline to compare the polysaccharide, a 7-valent conjugate vaccine, and hypothetical common antigen vaccine. The polysaccharide, conjugate, and common antigen vaccines prevented 10.6, 10.7, and 17.7% of invasive disease and 4.3, 5.6, and 10.0% of pneumonia, respectively. Superior effectiveness of new vaccines was dependent upon a presumed longer duration of protection than the 23V-PPV and effectiveness against noninvasive pneumonia. Our results suggest that new vaccines could improve disease prevention. (C) 2002 Published by Elsevier Science Ltd.