Pneumococcal vaccines currently cover only about 30% of known bacterial serotypes, leaving millions vulnerable to infection. *Streptococcus pneumoniae* kills roughly half a million people each year, with children under five and the elderly in lower-income countries hit hardest. Existing vaccines target the polysaccharide capsule that coats the bacterium, but because there are over 100 capsule variations, no vaccine can cover them all. Manufacturers also struggle with rising costs as they add more polysaccharides to each shot, and the strategy drives serotype replacement—where untargeted strains fill the gap left by vaccinated ones. This research proposes a fundamentally different approach. The team has identified a protein domain that is essential to all pneumococcal strains and remains hidden when bacteria are dormant but becomes exposed during active growth—the very phase linked to carriage, transmission, and disease. A vaccine targeting this domain would work across all serotypes, potentially replacing current limited-coverage shots with a single universal candidate. If successful in upcoming animal trials, this could eliminate the need for constant vaccine reformulation and dramatically reduce pneumococcal disease worldwide, especially in regions that currently bear the heaviest burden.
View original technical description
Streptococcus pneumoniae is the leading cause of bacterial death in children under 5 years old worldwide, however it is also capable of infecting other demographics, particularly the elderly and immunocompromised. With over half a billion infections worldwide, approximately half a million deaths are associated with the pneumococcus, and Lower Middle-Income Countries (LMIC) suffer disproportionately. Despite pneumococcal vaccines existing for several decades, total prevention and eradication remains elusive due to a myriad of reasons. Current vaccine technology relies on targeting the polysaccharide capsule which covers the surface of the pneumococccus. However, with over 100 variations (serotypes) of these polysaccharide capsules, total coverage is not possible with our current vaccine strategies. Present licensed vaccines (PCV13, PPSV23, PCV15 and PCV20) only target approximately 30% of all known serotypes. This low-valent solution is limited by current technology, expanding manufacturing costs as polysccahrides are added on, and serotype replacement disease, the major achilles heel of polysaccharide vaccines. Therefore, an alternative technology or target must be developed to combat pneumococcal disease across all of it serotypes. A recent discovery from our research group has shown that a highly conserved domain of an essential protein from Streptococcus pneumoniae confers protection against pneumococcus infection. Importantly this protein is essential to and present in, all pneumococcal strains. This domain remains in an inactive and shielded form when the bacteria are in a dormant state but becomes exposed during active cell growth. As growth is an essential part of carriage, transmission and eventually invasive disease, our vaccine candidate would target disease-causing bacteria without any implication for strain or serotype specificity, making this a novel universal (cross serotype) vaccine candidate, a long standing holy grail in the pneumococcal field. Our vaccine candidate protein has the potential to ultimately replace current polysaccharide pneumococcal vaccines with limited serotype coverage and could be the first universal vaccine aganist Streptococcus pneumoniae infection. The next step in our vaccine development pathway is a series of essential pre-clinical animal experiments focused on determining the protective efficacy of our identified protein domain against pneumococcal disease (invasive pneumonia and sepsis). This will provide the key pre-clinical data required to assess the efficacy of this strategy and the next steps for development of our vaccine development programme.
Plain English summaries and category classifications on this site are generated by AI and may not perfectly reflect the original research.
Is something wrong? Let us know