Vaccines against Streptococcus pneumoniae
James C. Paton
from: Vaccine Design: Innovative Approaches and Novel Strategies (Edited by: Rino Rappuoli and Fabio Bagnoli). Caister Academic Press, U.K. (2011)
Abstract
Existing vaccines against Streptococcus pneumoniae are targeted at the capsular polysaccharide (PS) of which there are 91 distinct serotypes. Polyvalent purified PS vaccines are immunogenic in healthy adults, but not in high risk groups such as young children and the elderly. Development of PS-protein conjugate vaccines has overcome the poor immunogenicity of PS in children, but the protection imparted is strictly serotype-specific, and the number of included serotypes is even more restricted than in the PS vaccine formulations. Widespread introduction of conjugate vaccines in developed countries has dramatically reduced the incidence of invasive pneumococcal disease due to serotypes included in the vaccine. However, these benefits are being eroded by increases in the incidence of disease caused by non-vaccine serotypes. Conjugate vaccines are also expensive, limiting their use in developing countries, where the burden of pneumococcal disease is greatest. Clearly, there is an urgent need to develop alternative pneumococcal vaccines that are (i) inexpensive, (ii) immunogenic in young children, and (iii) provide protection against all pneumococci regardless of serotype. Advances towards this goal are discussed herein, with particular emphasis on vaccines comprising pneumococcal proteins that contribute to virulence and are common to all serotypes read more ...
