Key Points - A 20% increase in reported cases following the introduction of new case definition criteria in 2002 - An overall 60% increase in cases from 2001 to 2003 compared to 1998–2000 - Peak incidence of meningococcal C in 2002 - Increase in case fatality rate in 2001–2003 - Stability in the number of cases of serogroup W135 (R.A.)