Antibody responses against pneumococcal polysaccharide antigens in vaccinated persons

The pneumococcal capsular polysaccharide vaccine protects healthy adults from pneumococcal infections. High-risk patients have generally impaired antibody responses and are only partly protected by vaccine. Infants less than 2 years old respond poorly to pneumococcal polysaccharide vaccine. But the pneumococcus is an important bacterial pathogen in young children and a protective vaccine is needed for this age group. The immunogenicity of capsular polysaccharides may be enhanced by preparing protein-polysaccharide conjugates and these preparations would help in the development of more effective vaccine for prevention of pneumococcal disease.