Spatial inequity in distribution of COVID-19 vaccination services in Aotearoa
Whitehead J, Atatoa P, Scott N, Lawrenson R. Spatial inequity in distribution of COVID-19 vaccination services in Aotearoa. Preprint on medRxiv. https://doi.org/10.1101/2021.08.26.21262647
This is a pre-print version. It has not been peer reviewed but is open access. The final publication (after peer review/editorial process) maybe (slightly) different and we will link to that when it is available.
From Jesse the lead author:
We examined the spatial accessibility of Covid-19 vaccination services across NZ at the start of the latest Covid-19 delta outbreak. We estimated access by looking at the number of vaccination services available to communities within a 30 minute drive, relative to the size of the local population. The locations of Covid-19 vaccinations services on the 18th August 2021 were distributed unevenly, and resulted in better spatial access for urban, wealthy, and European populations. Access was significantly worse for rural areas, Māori, older people, and areas of high socioeconomic deprivation. We also found significant variation in levels of access by DHB region. Furthermore, high access to Covid-19 vaccination services at the DHB level was associated with more equitable vaccination uptake for Māori. DHBs that provided the best access to vaccination services had the highest vaccination rate ratios for Māori.
Are we surprised?
Aim This research examines the spatial equity, and associated health equity implications, of the geographic distribution of Covid-19 vaccination services in Aotearoa New Zealand.
Method We mapped the distribution of Aotearoa’s population and used the enhanced-two-step-floating-catchment-method (E2SFCA) to estimate spatial access to vaccination services, taking into account service supply, population demand, and distance between populations and services. We used the Gini coefficient and both global and local measures of spatial autocorrelation to assess the spatial equity of vaccination services across Aotearoa. Additional statistics included an analysis of spatial accessibility for priority populations, including Māori (Indigenous people of Aotearoa), Pacific, over 65-year-olds, and people living in areas of high socioeconomic deprivation. We also examined vaccination service access according to rurality, and by District Health Board region.
Results Spatially accessibility to vaccination services varies across Aotearoa, and appears to be better in major cities than rural regions. A Gini coefficient of 0.426 confirms that spatial accessibility scores are not shared equally across the vaccine-eligible population. Furthermore, priority populations including Māori, older people, and residents of areas with socioeconomic constraint have, on average, statistically significantly lower spatial access to vaccination services. This is also true for people living in rural areas. Spatial access to vaccination services, also varies significantly by District Health Board (DHB) region as does equality of access, and the proportion of DHB priority population groups living in areas with poor access to vaccination services. A strong and significant positive correlation was identified between average spatial accessibility and the Māori vaccination rate ratio of DHBs.
Conclusion Covid-19 vaccination services in Aotearoa are not equitably distributed. Priority populations, with the most pressing need to receive Covid-19 vaccinations, have the worst access to vaccination services.