[Present view of conjugated pneumococcus vaccines]

Pneumococcal diseases cause substantial morbidity and mortality in both developed and developing countries. The only possible way how to control their occurrence is immunization. Multivalent plain polysaccharide vaccines recommended for elderly and chronically ill are however not effective in children under 2 years of age. This limitation can be overcome by coupling polysaccharides to a protein carrier that contains T-cell epitopes. The first pneumococcal conjugate vaccine was licensed in US in February 2000 as 7-valent vaccine conjugated on CRM197 protein. Implementation into immunization calendar resulted in sustainable reduction of invasive pneumococcal diseases by almost 80% and moderate effect on acute otitis media. Serotype coverage and replacement of vaccine serotype particularly by serotype 19A are the major limiting factors for global use. New candidate 9-valent vaccine proved significant reduction in overall morbidity in Gambia and 11-valent vaccine confirmed improved effect on acute otitis media.