Next generation pneumococcal vaccines

Currently licensed pneumococcal vaccines are based on the generation of antibodies to the pneumococcal polysaccharide, of which there are more than 90 different types. While these vaccines are highly effective against the serotypes included, their high cost and limited serotype coverage limit their usefulness worldwide, particularly in low resource areas. Thus alternative or adjunctive options are being actively pursued. This review will present these various approaches, including variations of the polysaccharide–protein conjugate strategy, protein-based strategies, and whole cell pneumococcal vaccines. The immunological basis for these different approaches is discussed as well.

► Currently licensed pneumococcal vaccines are effective but also have limitations for worldwide use. ► There is much interest in the development of novel, broad pneumococcal vaccines. ► Antibodies or effector T cells directed against conserved pneumococcal proteins are protective. ► Three novel vaccine approaches: modified conjugates, protein-based, or an inactivated whole cell vaccine.