Ethnic Disparities in Uptake of Pertussis Vaccination: A Focus on New Zealand Asians

Abstract

Introduction: New Zealand immunisation rates have improved steadily since the implementation of the National Immunisation Register (NIR) in 2005. However, differences in ethnicities still exist. Asians are known to have high immunisation uptake but little is known about the drivers of their health behaviours. Aims: To understand reasons for high immunisation rates among Asians, to review ethnic disparities in pertussis immunisation coverage and timeliness, and to investigate trends in pertussis-related hospitalisations. Methods: This thesis comprises three studies: two qualitative and one quantitative. The qualitative studies involved face-to-face interviews with Asian parents who had children less than five years old, and with practice nurses from practices with a high proportion of Asian patients. The quantitative study analysed data extracted from the National Health Index, the NIR, and the National Minimum Dataset to investigate rates of pertussis immunisation coverage and timeliness among different ethnic groups and deprivation quintiles. Trends in pertussis-related hospitalisations were also investigated. Findings: Reasons for high immunisation rates among Asians were found to be due to a combination of positive attitudes to immunisation arising from cultural attitudes of Asian parents, their trust in health professionals: being fully informed, facing minimal barriers, and having access to good immunisation services. Findings of both qualitative studies were similar, with practice nurses citing positive attitudes among Asian parents and being well-informed regarding immunisations. Positive attitudes among Asians were reflected in high immunisation uptake for the first dose of pertussis. Although other ethnicities reached similar coverage rates by the end of the pertussis immunisation series, timeliness of immunisations among Asians remained significantly higher at every dose compared to other ethnic groups. This correlated with the low pertussis-related hospitalisation observed among Asians. Conclusion: General practices can help facilitate high and timely immunisation levels. Practice protocols need to be appropriately shaped to support cultural practice such as distribution of immunisation-related information in multiple languages. Health professionals need to have current vaccinator training to alleviate parental concerns and encourage positive parental attitudes. Focus now needs to be on improving timeliness of immunisations and interventions such as pre-calls in general practices are important in improving timeliness of immunisation among other ethnic groups and therefore reduce the incidence of vaccine preventable diseases such as pertussis. Early enrolment of children in a general practice is also crucial to improve timeliness.