Routine vaccination with a single dose of conjugated meningococcal C vaccine at 14 months and a catch-up campaign have reduced the incidence of meningococcal C disease in the Netherlands. In contrast to countries where routine vaccination is given in infancy, vaccine failures were not reported. This suggests that one dose of conjugated vaccine in the second year of life might offer longer lasting protection against meningococcal C disease than 3 doses in infancy.