New conjugate vaccines for the prevention of pneumococcal disease in developing countries.

Current pneumococcal conjugate vaccines (PCVs) are highly effective in preventing serotype-specific pneumococcal disease; however, they are relatively expensive and complicated to produce. Furthermore, PCVs do not cover all disease-causing pneumococcal serotypes. While current PCVs are available in industrialized countries and with external assistance in some low-income countries, alternative, more intrinsically affordable pneumococcal vaccines are essential for achieving more widespread use and coverage in resource-limited settings, where vaccines are often inaccessible and need is greatest. This review article describes a number of approaches to develop new PCVs designed to meet this urgent need.