Streptococcus pneumoniae (the pneumococcus) is a major upper respiratory tract pathogen that causes severe illness and mortality. Pneumococcal infections can result in a wide spectrum of diseases, ranging from non-invasive diseases, such as otitis media and sinusitis, to invasive diseases, such as pneumonia, bacteremia (sepsis) and meningitis. Almost one million children in the developing world die of pneumococcal infections each year. The morbidity and mortality due to pneumococcal infections has been much reduced in the developing world during the last decade due to the introduction of the capsular polysaccharide conjugate vaccines for children. These pneumococcal vaccines are based on injected mixtures of a limited number of capsular polysaccharides, of which there are at least 92 different serotypes. The disadvantage of this type of vaccines is that they elicit protection only against the capsular types that are included in the vaccine. Consequently, disease caused by capsular types that are not in the vaccine is not prevented and these capsular types become more dominant in the population. This phenomenon is called serotype replacement.
Infections with pneumococci in humans are thought to always be preceded by nasal colonization. As a result, optimal protection against pneumococci is thought to require protection against colonization in addition to protection against invasive disease. The current polysaccharide-based vaccines have limitations in the prevention of pneumococcal colonization and in prevention of otitis media. Another disadvantage of the current pneumococcal vaccines for children is that they require expensive manufacturing technology and consequently the vaccines cannot be afforded by the majority of the low income countries. It is thought that these disadvantages can be overcome by developing new type of pneumococcal vaccines that are based on conserved pneumococcal protein antigens.
Our intranasal PneuGEM® vaccine is a subunit vaccine based on the validated bacterium-like-particle (BLP) based Mimopath® technology carrying proprietary conserved pneumococcal (surface) proteins. The PneuGEM® vaccine will include more than one selected protein antigen that is known to work well against colonization to achieve a broader and much more complete herd immunity. The vaccine will be highly protective against colonization with virtually all pneumococci, and thereby it should be possible to greatly minimize selective drift of pneumococci and future strain replacement. Intranasal PneuGEM® will also be targeted for the prevention of otitis media (middle ear infections) in children and pneumonia in elderly in high income countries.
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