In February 2000, the Food and Drug Administration approved the new heptavalent pneumococcal conjugate vaccine (Prevnar) for use in the USA. This approval was based on a number of studies, the most prominent of which was the Northern Kaiser Permanente Vaccine trial involving 37 868 children.1 In this study, children were randomised to receive either the heptavalent pneumococcal vaccine or an experimental vaccine of meningococcal C at 2, 4, 6, and 12 to 15 months of age. Children were followed for up to 24 months after vaccination. There were …