Streptococcus pneumoniae (the pneumococcus) is the leading killer of children under five years of age worldwide, predominantly affecting the developing world. Pneumococcal diseases include pneumonia, meningitis, septicaemia and otitis media (ear infection). Most children carry pneumococci asymptomatically in their nasopharynx, and this colonisation (carriage) is considered a prerequisite for disease. Our research examines the impact of vaccines on pneumococcal carriage, transmission and disease, incorporating both experimental and clinical studies. I will present recent data from our pneumococcal conjugate vaccine impact studies in the Asia Pacific region, as well as findings from murine models testing the therapeutic effect of a new whole-cell vaccine on pneumococcal carriage.