The preventable burden of pneumococcal disease in the developing world.

The efficacy of pneumococcal conjugate vaccines (PCV) and their remarkable success in operational use in North America challenge us to define the burden of pneumococcal disease and the likely benefits of PCV use in developing countries. Community-based incidence studies of invasive pneumococcal disease (IPD) and vaccine probe analyses of efficacy trials suggest there are approximately 814,000 pneumococcal deaths in children aged <5 years in developing countries each year and 1-4 million episodes of pneumococcal pneumonia in Africa alone. PCV will be effective where there is a demonstrable burden of IPD attributable to vaccine serotypes but herd protection and serotype replacement effects are unpredictable given existing knowledge of pneumococcal epidemiology in developing countries. Operational use of PCV in well-monitored settings is required to estimate these effects.