Pertussis (whooping cough) epidemiology in Waikato, New Zealand: 2000-2009

To describe the epidemiology of pertussis in the Waikato region of New Zealand between 2000 and 2009, and to identify any differences in case characteristics between epidemic and non-epidemic periods.

Waikato pertussis notification data for the period 1 January 2000 to 31 December 2009 was analysed to identify any trends in the rates and distribution of key variables. Characteristics of case notifications were compared between an identified epidemic and non-epidemic period.

Pertussis notification rates in the Waikato region were higher than national rates but followed a similar yearly pattern. Epidemics were identified in the years 2000 and 2004. The age distribution of pertussis cases changed over the decade with an increasing percentage in older age groups. Notification rates were higher in Europeans than Maori and in the least deprived NZDep group compared to the most deprived. In contrast, hospitalisation rates were higher in Maori than Europeans and in the most deprived NZDep groups. No clear differences in case characteristics were identified between an epidemic and non-epidemic period.

The epidemiology of pertussis in Waikato is similar to that reported elsewhere in New Zealand. Further studies are required to clearly identify whether there are differences in case characteristics between epidemic and non-epidemic periods.