Measuring disparities in immunisation coverage among children in New Zealand

For the past 20 years, New Zealand has experienced low immunisation coverage levels. Following the introduction of the National Immunisation Register (NIR) in 2005 many practitioners envisaged improved overall immunisation uptake through enhanced surveillance and monitoring capacities. This study aimed to investigate the geographical distribution and variables associated with disparities in immunisation uptake in New Zealand using a large NIR data set of children aged 12 months old in 2007-2009. DHB immunisation uptake was adjusted for individual ethnicity and deprivation status, year of birth and geographic location. Substantial variations in uptake by ethnicity and District Health Board (DHB) level were evident. Māori (NZ indigenous) and 'Other' ethnicity remain a substantial risk factor for low immunisation uptake after controlling for socio-economic deprivation. In addition, a general north-south gradient was confirmed across New Zealand. Current immunisation programme strategies for planners and providers in New Zealand need to recognise varying DHB compositions in order to provide efficient service provision and to focus on those groups at higher risk of not being immunised.