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Aotearoa New Zealand’s (hereafter Aotearoa) management strategy against COVID-19 put the country in a good position internationally with relatively few deaths or active COVID-19 cases for most of 2020 and 2021.[[1]] The Government’s vaccination delivery programme has become increasingly important to save morbidity and mortality. The community outbreak of the Delta variant of COVID-19 on 17 August 2021 highlights that, until the vaccination rollout is complete, there is a continued risk. Achieving the equitable and universal delivery of a vaccine is therefore essential to help protect all residents of Aotearoa, and particularly priority populations who are at greatest risk of risk of infection, and most vulnerable to COVID-19 severity. Achieving equitable health outcomes means prioritising some populations with better access and resourcing.[[2]]

In its vaccination rollout[[3,4]] (see Text Box 1) the Government has prioritised border and MIQ workers, frontline healthcare workers, older people, and those with ‘relevant’ underlying health conditions. However, internationally, arguments have been made for the allocation of COVID-19 vaccines according to not only individual risk, but also social vulnerabilities—such as socio-economic status, occupation, housing and living conditions, ethnicity, and other factors that limit access to healthcare.[[5]] Indigenous populations must also be prioritised.[[6]] The health impact of COVID-19 is likely to be higher among Māori and other Indigenous populations.[[7,8]] There are stark, persistent, and increasing health inequities in Aotearoa experienced particularly by Indigenous Māori, that occur across the life course and are well documented.[[2,9,10]] Māori are disproportionately impacted by poorer access to the social determinants of health, including housing, quality healthcare,[[11]] and racism in the health system and wider society.[[12–15]]

Achieving equitable immunisation necessarily involves balancing the logistical constraints of distributing and administering the time and temperature sensitive COVID-19 vaccine, with minimising barriers for those who wish to receive it. There are various ways of conceptualising ‘fairness’ and prioritising vaccine delivery,[[5,16]] which in turn can have different impacts on COVID-19 related deaths, hospitalisations, and ICU admissions.[[17]] A major priority should be to immunise people who might otherwise die if they contract COVID-19, while a secondary aim is to reduce admissions to hospital and to protect the health system. In this paper, priority populations therefore include Māori, Pasifika, people aged 65 and over, people with comorbidities and those living in areas of high socio-economic deprivation.[[18]] As noted, the vaccine rollout in Aotearoa has taken a phased approach, grouping populations according to priority and risk.[[19]] View Text Box 1.

The Pfizer vaccine has been offered across Aotearoa at a range of locations acting as vaccination services, including some general practitioner (GP) clinics and pharmacies. It has also been offered at a range of new ‘pop-up’ clinics at sports grounds, marae, and stadium mega-clinics.[[20]] Decision-making and the implementation of the vaccine rollout has been devolved to District Health Boards (DHBs) who are responsible for the health of the populations in their region.

Spatial accessibility and spatial equity

The racialised inequitable access to and uptake of COVID-19 vaccination seen internationally,[[5,21,22]] could occur in Aotearoa, where access to healthcare is inequitable.[[23–25]] Additional barriers to accessing healthcare, particularly for Māori, include the (in)appropriateness, (un)availability, (in)acceptability and poorer quality care provided by many services.[[26–29]] Māori and Pasifika people report experiencing racism from healthcare providers,[[12–15]] and are disproportionately affected by cost and transport as barriers to accessing GP services.[[30]] Barriers to vaccine access that disproportionately affect priority populations—with the most risk of COVID-19 severity—will exacerbate key inequities. Health authorities should aim for an equitable and universal vaccine rollout which ensures spatial equity—giving priority populations appropriately higher access to vaccination services and opportunities for vaccination. This paper examines the spatial equity of the vaccine rollout in Aotearoa with a particular focus on priority populations.

Methodology

Key steps

Four key steps were taken in the assessment of the spatial equity of COVID-19 vaccination services.

Figure 1: Key steps in assessing the spatial equity of COVID-19 vaccination services.

Data gathering

The population data is based on 2018 census data at the Statistical Area 1 (SA1) level, which includes information on the usually resident population, age, and Ethnicity of Residents in each SA1.[[31]] The population aged 15 and over was used to represent the ‘vaccine eligible’ population at the time of analysis. Socio-economic constraint was estimated with the 2018 New Zealand Index of Socioeconomic Deprivation (NZDep18).[[32]] The Geographic Classification for Health (GCH)[[33]] was used to define rural and urban areas of Aotearoa. Travel times were estimated using Beere’s road network layer.[[34]] COVID-19 vaccination services locations were downloaded on 18 August 2021 from the Healthpoint[[20]] website. Vaccination services were linked to the Ministry of Health Facilities dataset,[[35]] which includes XY coordinates for all health facilities in Aotearoa. Since no service volume data were available it was assumed in all calculations that service volume is equal at all sites.

Spatial accessibility

Geographic Information Systems (GIS) were used to quantify the spatial equity of COVID-19 vaccination services. The three steps to spatial equity analysis involve defining, estimating and quantifying spatial equity.[[36]] Spatial equity usually refers to a fair distribution of resources relative to need.[[37]] In order to achieve equitable health outcomes, some populations should be prioritised and have better access to services.[[2]] Floating Catchment Area (FCA) techniques estimate accessibility by considering service availability relative to population size and the distance between populations and services to produce an accessibility score for each small area unit within a study area. This paper applied the enhanced two-step floating catchment area method (E2SFCA)[[38]] to estimate accessibility to COVID-19 vaccination services in Aotearoa, using the 30-minute drivetime catchments originally proposed.[[39]]

Spatial equity

Once overall levels of accessibility have been estimated, the Gini coefficient can be used to quantify equality. The Gini coefficient assesses the distribution of resources (such as income, or in this case, accessibility) across a population, and provides an equality score between zero and one, with zero representing a perfectly equal distribution and one indicating a completely unequal distribution.[[40]] To examine the equality of spatial access to COVID-19 vaccination services, the population weighted Gini coefficient was calculated in R.

Although the Gini coefficient gives an indication of whether the distribution of spatial accessibility to vaccination services is equal, it does not indicate whether such a distribution is equitable. For instance, in a system where the entire vaccine eligible population has the same level of access to vaccination services, access would be inequitable for priority populations. Therefore, it is important to examine which locations and populations have high or low levels of access to services. The presence of statistically significant clustering of spatial accessibility scores was tested using Global Moran’s I measure of spatial autocorrelation. Anselin’s Local Indicator of Spatial Autocorrelation Moran’s I (LISA) was also calculated to map the locations of statistically significant clusters of high and low access.

Additional statistical analysis

Additional statistical tests were undertaken to determine whether spatial access to vaccination services varied for priority populations—particularly for Māori, Pasifika, older people, and those living in areas of high socio-economic deprivation. Differences in spatial access to vaccination services between rural and urban areas of Aotearoa were also examined. To establish whether median spatial accessibility scores, as estimated by the E2SFCA, vary significantly for different population groups, Mann-Whitney tests were performed. A Kurskal-Wallis test and Mann-Whitney test were also used to determine whether there was a statistically significant difference in the median spatial accessibility scores for each DHB region. The proportion of each priority population group living in areas with poor vaccination access was calculated for each DHB region.

Results

Spatial accessibility

In total 447 vaccination services were identified, of which 212 (47%) were GP clinics, 91 (20%) were pharmacies, 50 (11%) appeared to be DHB-run dedicated vaccination centres, and 28 (6%) appeared to be iwi led, or run by Māori or Pasifika providers. Figure 2 shows the locations of these vaccination services and indicates the geographic distribution of spatial accessibility scores across Aotearoa. Scores were sorted into quintiles, with Quintile 1 (Q1—best access) represented in light red and Quintile 5 (Q5—worst access) in dark red. While access to COVID-19 vaccination services in large cities is generally good, there are large parts of rural Aotearoa with poor access. Of the major centres, Ōtautahi appears to have the worst access, while Te Whanganui-a-Tara and Ōtepoti have good levels of access to vaccination clinics. View Figure 2.

Spatial equity

Gini coefficient

A Gini coefficient of 0.426 was calculated, suggesting an unequal distribution of vaccination services.

Spatial autocorrelation

Global Moran’s I returned a statistically significant result (I=0.349, p<0.00), indicating that spatial accessibility scores were clustered. The LISA analysis results (Figure 3) indicate where those clusters are. Dark green represents high-high clusters, which are statistically significant clusters of areas of high accessibility surrounded by other high access areas. Areas in light green are high-low outliers, which have high accessibility but are surrounded by areas with low access. Similarly, the dark blue regions represent low-low clusters, while light blue areas are low-high outliers. Clusters of high accessibility tend to be in major cities, while rural and remote areas of Aotearoa have clusters of poor access to vaccination services. View Figure 3.

Additional statistical analysis

Further statistical analysis indicates that differences in access to vaccination services negatively affect priority populations, and are therefore inequitable. Table 1 displays the median spatial accessibility scores of different types of neighbourhoods. Higher spatial accessibility scores indicate better spatial access to vaccination services. Spatial accessibility scores across Aotearoa ranged from 0.0 to 382.4, with an average score of 13.6, a median score of 11.1, and an interquartile range (IQR) of 12.2. View Table 1.

Mann-Whitney tests revealed statistically significant differences in the median spatial accessibility scores of some types of neighbourhoods. Areas with a higher proportion of Māori residents (>15%) had statistically significantly worse access to vaccination services than neighbourhoods with a lower proportion of Māori residents (p<.001). Access to vaccination services was also worse in neighbourhoods with a high proportion of Pasifika residents (>8%) compared to areas with a low proportion of Pasifika residents (p<.001). Similarly, neighbourhoods with a higher proportion of over 65-year-olds (>15%) had worse access to vaccine services than areas with a lower proportion of over 65-year-olds (p<.001). Rural residents also had worse access to vaccination services than residents of urban areas (p<.001). A Kruskal-Wallis rank sum test also revealed a statistically significant difference between accessibility scores across the five quintiles of socio-economic deprivation. Neighbourhoods with high levels of socio-economic deprivation had higher median access scores than neighbourhoods in NZDep18 quintiles 1–4 (p<.001).

A statistically significant difference between median DHB levels of spatial accessibility was determined by a Kruskal-Wallis rank sum test (H[[2]]=17643.3, p<.001). Table 2 shows, for each DHB region, the median spatial accessibility score, Gini coefficient, and the proportion of each priority population group (and total eligible population) living in an area with poor spatial access (Q5) to vaccination services. Table 2 also displays vaccination rate ratios for Māori and Pasifika residents of each DHB region, indicating the relative proportion of Māori and Pasifika people who have received two vaccine doses, as compared to non-Māori and non-Pasifika residents. DHBs with higher levels of average spatial accessibility appear to have more equitable vaccine uptake for Māori and Pasifika people. A strong and statistically significant correlation was identified between DHBs’ median levels of spatial accessibility and vaccination rate ratios for Māori (r=.69, p<.001) but not Pasifika (r=.36, p=.112) as at 20 August 2021. The median DHB levels of spatial accessibility (estimated in this paper at 18 August 2021) continued to be associated with vaccination rate ratios for Māori on 6 November 2021, with a moderate correlation identified (r=0.47, p<0.05). Strong and statistically significant negative relationships were also identified between the proportion of Māori living in areas of low spatial access to vaccination services, and the vaccination rate ratios for Māori at both 20 August 2021 (r=-.68, p<.001) and 6 November 2021 (r=-.60, p<.01). This indicates that DHB regions with a higher proportion of Māori living in areas with poor access to vaccination services are likely to also have more inequitable vaccination uptake, with lower rates for Māori than non-Māori residents. Weak and non-significant correlations were identified between DHBs’ Gini coefficients and vaccination rate ratios for Māori (r=-.08, p=.75) and Pacific (r=-.15, p=.52). View Table 2.

Discussion

This work has some limitations. The E2SFCA uses drive-time-based catchments to calculate spatial accessibility to services. One key limitation of this approach is the inherent assumption that all residents of an SA1 have access to a private vehicle (with a current warrant of fitness) and are able to afford petrol. Residents in neighbourhoods with higher levels of socio-economic deprivation (who are disproportionately Māori and Pasifika) are less likely to have access to a motor vehicle or be able to cover additional or unplanned transportation costs. Likewise, the E2SFCA does not assess the wider, non-spatial, domains of access. Vaccination services listed on the Healthpoint website are likely to be accurate and reflective of the actual services available on 18 August 2021, but will not reflect additional clinics that have been added in response to the COVID-19 Delta variant outbreak. This analysis does not include any vaccination services that are not listed on the Healthpoint website. No information was available on the capacity of vaccination services, the availability of appointments, or the different service models that may have been used by vaccination services. This may have resulted in an underestimate of accessibility in some urban areas, and an overestimate of accessibility in some rural areas—potentially further exacerbating inequities in vaccination accessibility. While data availability and quality is beyond the control and scope of this paper, it highlights the importance of strong public health intelligence, including the collection and maintenance of information on service delivery. Issues with the implementation of the 2018 census[[42]] mean that the quality of the ethnicity variable has been independently rated as ‘moderate’.[[43]] Additionally, other census variables may have impacted on the quality of NZDep18. Furthermore, ethnicity data in the 2018 census are not prioritised, so individuals who report multiple ethnicities are counted more than once.[[44]] Therefore the results presented in this paper are population estimates using the best available data.

Despite these limitations, this analysis indicates that, as predicted previously,[[18]] spatial access to vaccination services across Aotearoa is inequitable. Māori, Pasifika people, over 65-year-olds, and rural residents have worse access to vaccination services. Given the higher burden of disease, and increased likelihood of severe COVID-19 infection outcomes in these groups, priority populations must have opportunities to become vaccinated as soon as possible. Health authorities have had opportunities to work with priority communities to ensure an equitable vaccination rollout. Vaccination services locations could have been proactively planned to target priority populations and maximise access opportunities for these groups. The fact that more than two-thirds of vaccination services were run from health facilities such as GP clinics, pharmacies, and hospitals suggest that authorities have relied on current health services, regardless of their inequitable distribution already highlighted in the research literature.[[18,25,29]] This decision appears to have resulted in a disproportionately poor access to COVID-19 vaccination for older people, Māori, Pasifika, and rural people, all groups who are at risk of severe outcomes from COVID-19 infection.

These findings add to the body of research describing spatial inequities in the Aotearoa health system, across a range of health services,[[29,45,46]] and provides additional context that may be relevant to recent findings of geographic variation in childhood immunisation rates.[[47]] It also highlights that even when new health services (such as COVID-19 vaccination services) are added to the health system there is no guarantee that they will be equitably distributed. If there is no clear planning, guidance, or monitoring for pro-equity service distributions, the result is inevitably inequitable access that compounds existing health inequities. Although health services are only one component of the social determinants that shape the distribution and equity of health outcomes, they are an aspect that health authorities are theoretically able to influence. Ensuring the fair distribution of health services, to improve access for populations with the highest health needs and risk of severe outcomes, is one action that health authorities can take to improve health equity in Aotearoa. It is becoming increasingly important that the Māori Health Authority and Health NZ monitor, and improve, the spatial equity of all health services in Aotearoa. These research findings emphasise the importance of and need for national strategies that make use of both geospatial and public health intelligence to guide a national vaccination rollout—and the equitable delivery of health services in general. As the health system reforms in Aotearoa, this research can inform approaches to monitor and improve the spatial equity of a wide range of health services.

The finding of significantly lower spatial access to COVID-19 vaccination services for communities with a higher proportion of Māori residents, and that more than a quarter of Māori live in areas with low access to vaccination services, indicates structural racism in Aotearoa New Zealand’s COVID-19 vaccination rollout. In combination with an age-based prioritisation for vaccinations that has held back a large proportion of the structurally younger Māori population,[[48]] and individual experiences of racism within the health system,[[12–15]] this has left a disproportionate number of Māori unvaccinated against COVID-19. International evidence indicates that geographic and ethnic targeting of vaccination services results in more equitable uptakes and avoids more deaths than age-based prioritisation alone.[[49]] This underlines that the COVID-19 vaccination rollout has failed to protect Māori, and reinforces the urgent need for an independent Māori Health Authority, with a service commissioning mandate, to design and deliver effective and equitable services for Māori.

The results also highlight significant variation in levels of access—and inequity of access between DHBs. This is not surprising, as localised decision-making around the delivery of COVID-19 vaccinations has been devolved from the Ministry of Health to DHBs, which are likely to have followed different vaccine rollout plans, had different levels of partnership with iwi, and relied on the existing distribution of health facilities—which already provide differing levels of access to services across DHBs. These differences in access and spatial equity between DHBs appears to be associated with the equity of vaccine uptake for Māori. As at 20 August 2021, Capital & Coast DHB had both the highest average level and most even distribution of spatial access to vaccination services, and high relative vaccination rates for Māori living in the region. Similarly, Southern DHB had high levels of average access to services, and the highest relative vaccination rate for Māori. On the other hand, DHBs which are providing low levels of spatial access to vaccination services, such as Lakes, Northland, Bay of Plenty and Whanganui, all had low vaccination rate ratios for Māori (0.48–0.52).

Improving the spatial equity of COVID-19 vaccination services, by offering additional services in areas with high priority populations and low access to current vaccination services, will be important for improving the equity of vaccination uptake and protecting priority populations. Previous research suggests that vaccinations delivered at schools would offer good access to 99.9% of the total population.[[18]] School-based vaccinations could contribute to a more equitable paediatric vaccine rollout, and may also reach as-yet-unvaccinated adults. While many rural and socio-economically constrained populations are at high risk of severe outcomes from COVID-19 infection,[[50]] the Ministry of Health has not at the time of writing reported vaccination rates according to area-level socio-economic deprivation, or rural-urban status. However, independent analysis suggests that the overall vaccination rollout for rural people is also inequitable.[[51]] While a flurry of additional vaccination sites has appeared since the start of the Delta outbreak in Aotearoa, ongoing monitoring suggests that access has not substantially improved in rural areas.[[52]] Additional research examining changes in spatial access and equity throughout the Delta outbreak is currently underway. Before Aotearoa can consider loosening international and internal border restrictions, or removing protective public health measures, it is essential to achieve high vaccination rates among priority populations who will experience the most severe health outcomes from COVID-19 infection.

Summary

Abstract

Aim

To examine the spatial equity, and associated health equity implications, of the geographic distribution of COVID-19 vaccination services in Aotearoa New Zealand.

Method

The distribution of Aotearoa’s population was mapped, and the enhanced two-step floating catchment method (E2SFCA) applied to estimate spatial access to vaccination services. The Gini coefficient and spatial autocorrelation measures assessed the spatial equity of vaccination services. Additional statistics included an analysis of spatial accessibility for priority populations, and by District Health Board (DHB) region.

Results

Spatial 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, Pasifika, and older people have 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 DHB region as does the Gini coefficient, 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.

Author Information

Jesse Whitehead: Te Ngira: Institute for Population Research (formerly NIDEA), University of Waikato, Hamilton, New Zealand. Polly Atatoa Carr: Te Ngira: Institute for Population Research (formerly NIDEA), University of Waikato, Hamilton, New Zealand; Waikato District Health Board, Hamilton, New Zealand. Nina Scott: Waikato District Health Board, Hamilton, New Zealand. Ross Lawrenson: Waikato District Health Board, Hamilton, New Zealand; Waikato Medical Research Group, University of Waikato, Hamilton, New Zealand.

Acknowledgements

Correspondence

Jesse Whitehead, University of Waikato, Gate 1 Knighton Road, Hamilton New Zealand, +64 7 838 4040 (phone), +64 7 838 4621 (fax).

Correspondence Email

jesse.whitehead@waikato.ac.nz

Competing Interests

Nil.

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Aotearoa New Zealand’s (hereafter Aotearoa) management strategy against COVID-19 put the country in a good position internationally with relatively few deaths or active COVID-19 cases for most of 2020 and 2021.[[1]] The Government’s vaccination delivery programme has become increasingly important to save morbidity and mortality. The community outbreak of the Delta variant of COVID-19 on 17 August 2021 highlights that, until the vaccination rollout is complete, there is a continued risk. Achieving the equitable and universal delivery of a vaccine is therefore essential to help protect all residents of Aotearoa, and particularly priority populations who are at greatest risk of risk of infection, and most vulnerable to COVID-19 severity. Achieving equitable health outcomes means prioritising some populations with better access and resourcing.[[2]]

In its vaccination rollout[[3,4]] (see Text Box 1) the Government has prioritised border and MIQ workers, frontline healthcare workers, older people, and those with ‘relevant’ underlying health conditions. However, internationally, arguments have been made for the allocation of COVID-19 vaccines according to not only individual risk, but also social vulnerabilities—such as socio-economic status, occupation, housing and living conditions, ethnicity, and other factors that limit access to healthcare.[[5]] Indigenous populations must also be prioritised.[[6]] The health impact of COVID-19 is likely to be higher among Māori and other Indigenous populations.[[7,8]] There are stark, persistent, and increasing health inequities in Aotearoa experienced particularly by Indigenous Māori, that occur across the life course and are well documented.[[2,9,10]] Māori are disproportionately impacted by poorer access to the social determinants of health, including housing, quality healthcare,[[11]] and racism in the health system and wider society.[[12–15]]

Achieving equitable immunisation necessarily involves balancing the logistical constraints of distributing and administering the time and temperature sensitive COVID-19 vaccine, with minimising barriers for those who wish to receive it. There are various ways of conceptualising ‘fairness’ and prioritising vaccine delivery,[[5,16]] which in turn can have different impacts on COVID-19 related deaths, hospitalisations, and ICU admissions.[[17]] A major priority should be to immunise people who might otherwise die if they contract COVID-19, while a secondary aim is to reduce admissions to hospital and to protect the health system. In this paper, priority populations therefore include Māori, Pasifika, people aged 65 and over, people with comorbidities and those living in areas of high socio-economic deprivation.[[18]] As noted, the vaccine rollout in Aotearoa has taken a phased approach, grouping populations according to priority and risk.[[19]] View Text Box 1.

The Pfizer vaccine has been offered across Aotearoa at a range of locations acting as vaccination services, including some general practitioner (GP) clinics and pharmacies. It has also been offered at a range of new ‘pop-up’ clinics at sports grounds, marae, and stadium mega-clinics.[[20]] Decision-making and the implementation of the vaccine rollout has been devolved to District Health Boards (DHBs) who are responsible for the health of the populations in their region.

Spatial accessibility and spatial equity

The racialised inequitable access to and uptake of COVID-19 vaccination seen internationally,[[5,21,22]] could occur in Aotearoa, where access to healthcare is inequitable.[[23–25]] Additional barriers to accessing healthcare, particularly for Māori, include the (in)appropriateness, (un)availability, (in)acceptability and poorer quality care provided by many services.[[26–29]] Māori and Pasifika people report experiencing racism from healthcare providers,[[12–15]] and are disproportionately affected by cost and transport as barriers to accessing GP services.[[30]] Barriers to vaccine access that disproportionately affect priority populations—with the most risk of COVID-19 severity—will exacerbate key inequities. Health authorities should aim for an equitable and universal vaccine rollout which ensures spatial equity—giving priority populations appropriately higher access to vaccination services and opportunities for vaccination. This paper examines the spatial equity of the vaccine rollout in Aotearoa with a particular focus on priority populations.

Methodology

Key steps

Four key steps were taken in the assessment of the spatial equity of COVID-19 vaccination services.

Figure 1: Key steps in assessing the spatial equity of COVID-19 vaccination services.

Data gathering

The population data is based on 2018 census data at the Statistical Area 1 (SA1) level, which includes information on the usually resident population, age, and Ethnicity of Residents in each SA1.[[31]] The population aged 15 and over was used to represent the ‘vaccine eligible’ population at the time of analysis. Socio-economic constraint was estimated with the 2018 New Zealand Index of Socioeconomic Deprivation (NZDep18).[[32]] The Geographic Classification for Health (GCH)[[33]] was used to define rural and urban areas of Aotearoa. Travel times were estimated using Beere’s road network layer.[[34]] COVID-19 vaccination services locations were downloaded on 18 August 2021 from the Healthpoint[[20]] website. Vaccination services were linked to the Ministry of Health Facilities dataset,[[35]] which includes XY coordinates for all health facilities in Aotearoa. Since no service volume data were available it was assumed in all calculations that service volume is equal at all sites.

Spatial accessibility

Geographic Information Systems (GIS) were used to quantify the spatial equity of COVID-19 vaccination services. The three steps to spatial equity analysis involve defining, estimating and quantifying spatial equity.[[36]] Spatial equity usually refers to a fair distribution of resources relative to need.[[37]] In order to achieve equitable health outcomes, some populations should be prioritised and have better access to services.[[2]] Floating Catchment Area (FCA) techniques estimate accessibility by considering service availability relative to population size and the distance between populations and services to produce an accessibility score for each small area unit within a study area. This paper applied the enhanced two-step floating catchment area method (E2SFCA)[[38]] to estimate accessibility to COVID-19 vaccination services in Aotearoa, using the 30-minute drivetime catchments originally proposed.[[39]]

Spatial equity

Once overall levels of accessibility have been estimated, the Gini coefficient can be used to quantify equality. The Gini coefficient assesses the distribution of resources (such as income, or in this case, accessibility) across a population, and provides an equality score between zero and one, with zero representing a perfectly equal distribution and one indicating a completely unequal distribution.[[40]] To examine the equality of spatial access to COVID-19 vaccination services, the population weighted Gini coefficient was calculated in R.

Although the Gini coefficient gives an indication of whether the distribution of spatial accessibility to vaccination services is equal, it does not indicate whether such a distribution is equitable. For instance, in a system where the entire vaccine eligible population has the same level of access to vaccination services, access would be inequitable for priority populations. Therefore, it is important to examine which locations and populations have high or low levels of access to services. The presence of statistically significant clustering of spatial accessibility scores was tested using Global Moran’s I measure of spatial autocorrelation. Anselin’s Local Indicator of Spatial Autocorrelation Moran’s I (LISA) was also calculated to map the locations of statistically significant clusters of high and low access.

Additional statistical analysis

Additional statistical tests were undertaken to determine whether spatial access to vaccination services varied for priority populations—particularly for Māori, Pasifika, older people, and those living in areas of high socio-economic deprivation. Differences in spatial access to vaccination services between rural and urban areas of Aotearoa were also examined. To establish whether median spatial accessibility scores, as estimated by the E2SFCA, vary significantly for different population groups, Mann-Whitney tests were performed. A Kurskal-Wallis test and Mann-Whitney test were also used to determine whether there was a statistically significant difference in the median spatial accessibility scores for each DHB region. The proportion of each priority population group living in areas with poor vaccination access was calculated for each DHB region.

Results

Spatial accessibility

In total 447 vaccination services were identified, of which 212 (47%) were GP clinics, 91 (20%) were pharmacies, 50 (11%) appeared to be DHB-run dedicated vaccination centres, and 28 (6%) appeared to be iwi led, or run by Māori or Pasifika providers. Figure 2 shows the locations of these vaccination services and indicates the geographic distribution of spatial accessibility scores across Aotearoa. Scores were sorted into quintiles, with Quintile 1 (Q1—best access) represented in light red and Quintile 5 (Q5—worst access) in dark red. While access to COVID-19 vaccination services in large cities is generally good, there are large parts of rural Aotearoa with poor access. Of the major centres, Ōtautahi appears to have the worst access, while Te Whanganui-a-Tara and Ōtepoti have good levels of access to vaccination clinics. View Figure 2.

Spatial equity

Gini coefficient

A Gini coefficient of 0.426 was calculated, suggesting an unequal distribution of vaccination services.

Spatial autocorrelation

Global Moran’s I returned a statistically significant result (I=0.349, p<0.00), indicating that spatial accessibility scores were clustered. The LISA analysis results (Figure 3) indicate where those clusters are. Dark green represents high-high clusters, which are statistically significant clusters of areas of high accessibility surrounded by other high access areas. Areas in light green are high-low outliers, which have high accessibility but are surrounded by areas with low access. Similarly, the dark blue regions represent low-low clusters, while light blue areas are low-high outliers. Clusters of high accessibility tend to be in major cities, while rural and remote areas of Aotearoa have clusters of poor access to vaccination services. View Figure 3.

Additional statistical analysis

Further statistical analysis indicates that differences in access to vaccination services negatively affect priority populations, and are therefore inequitable. Table 1 displays the median spatial accessibility scores of different types of neighbourhoods. Higher spatial accessibility scores indicate better spatial access to vaccination services. Spatial accessibility scores across Aotearoa ranged from 0.0 to 382.4, with an average score of 13.6, a median score of 11.1, and an interquartile range (IQR) of 12.2. View Table 1.

Mann-Whitney tests revealed statistically significant differences in the median spatial accessibility scores of some types of neighbourhoods. Areas with a higher proportion of Māori residents (>15%) had statistically significantly worse access to vaccination services than neighbourhoods with a lower proportion of Māori residents (p<.001). Access to vaccination services was also worse in neighbourhoods with a high proportion of Pasifika residents (>8%) compared to areas with a low proportion of Pasifika residents (p<.001). Similarly, neighbourhoods with a higher proportion of over 65-year-olds (>15%) had worse access to vaccine services than areas with a lower proportion of over 65-year-olds (p<.001). Rural residents also had worse access to vaccination services than residents of urban areas (p<.001). A Kruskal-Wallis rank sum test also revealed a statistically significant difference between accessibility scores across the five quintiles of socio-economic deprivation. Neighbourhoods with high levels of socio-economic deprivation had higher median access scores than neighbourhoods in NZDep18 quintiles 1–4 (p<.001).

A statistically significant difference between median DHB levels of spatial accessibility was determined by a Kruskal-Wallis rank sum test (H[[2]]=17643.3, p<.001). Table 2 shows, for each DHB region, the median spatial accessibility score, Gini coefficient, and the proportion of each priority population group (and total eligible population) living in an area with poor spatial access (Q5) to vaccination services. Table 2 also displays vaccination rate ratios for Māori and Pasifika residents of each DHB region, indicating the relative proportion of Māori and Pasifika people who have received two vaccine doses, as compared to non-Māori and non-Pasifika residents. DHBs with higher levels of average spatial accessibility appear to have more equitable vaccine uptake for Māori and Pasifika people. A strong and statistically significant correlation was identified between DHBs’ median levels of spatial accessibility and vaccination rate ratios for Māori (r=.69, p<.001) but not Pasifika (r=.36, p=.112) as at 20 August 2021. The median DHB levels of spatial accessibility (estimated in this paper at 18 August 2021) continued to be associated with vaccination rate ratios for Māori on 6 November 2021, with a moderate correlation identified (r=0.47, p<0.05). Strong and statistically significant negative relationships were also identified between the proportion of Māori living in areas of low spatial access to vaccination services, and the vaccination rate ratios for Māori at both 20 August 2021 (r=-.68, p<.001) and 6 November 2021 (r=-.60, p<.01). This indicates that DHB regions with a higher proportion of Māori living in areas with poor access to vaccination services are likely to also have more inequitable vaccination uptake, with lower rates for Māori than non-Māori residents. Weak and non-significant correlations were identified between DHBs’ Gini coefficients and vaccination rate ratios for Māori (r=-.08, p=.75) and Pacific (r=-.15, p=.52). View Table 2.

Discussion

This work has some limitations. The E2SFCA uses drive-time-based catchments to calculate spatial accessibility to services. One key limitation of this approach is the inherent assumption that all residents of an SA1 have access to a private vehicle (with a current warrant of fitness) and are able to afford petrol. Residents in neighbourhoods with higher levels of socio-economic deprivation (who are disproportionately Māori and Pasifika) are less likely to have access to a motor vehicle or be able to cover additional or unplanned transportation costs. Likewise, the E2SFCA does not assess the wider, non-spatial, domains of access. Vaccination services listed on the Healthpoint website are likely to be accurate and reflective of the actual services available on 18 August 2021, but will not reflect additional clinics that have been added in response to the COVID-19 Delta variant outbreak. This analysis does not include any vaccination services that are not listed on the Healthpoint website. No information was available on the capacity of vaccination services, the availability of appointments, or the different service models that may have been used by vaccination services. This may have resulted in an underestimate of accessibility in some urban areas, and an overestimate of accessibility in some rural areas—potentially further exacerbating inequities in vaccination accessibility. While data availability and quality is beyond the control and scope of this paper, it highlights the importance of strong public health intelligence, including the collection and maintenance of information on service delivery. Issues with the implementation of the 2018 census[[42]] mean that the quality of the ethnicity variable has been independently rated as ‘moderate’.[[43]] Additionally, other census variables may have impacted on the quality of NZDep18. Furthermore, ethnicity data in the 2018 census are not prioritised, so individuals who report multiple ethnicities are counted more than once.[[44]] Therefore the results presented in this paper are population estimates using the best available data.

Despite these limitations, this analysis indicates that, as predicted previously,[[18]] spatial access to vaccination services across Aotearoa is inequitable. Māori, Pasifika people, over 65-year-olds, and rural residents have worse access to vaccination services. Given the higher burden of disease, and increased likelihood of severe COVID-19 infection outcomes in these groups, priority populations must have opportunities to become vaccinated as soon as possible. Health authorities have had opportunities to work with priority communities to ensure an equitable vaccination rollout. Vaccination services locations could have been proactively planned to target priority populations and maximise access opportunities for these groups. The fact that more than two-thirds of vaccination services were run from health facilities such as GP clinics, pharmacies, and hospitals suggest that authorities have relied on current health services, regardless of their inequitable distribution already highlighted in the research literature.[[18,25,29]] This decision appears to have resulted in a disproportionately poor access to COVID-19 vaccination for older people, Māori, Pasifika, and rural people, all groups who are at risk of severe outcomes from COVID-19 infection.

These findings add to the body of research describing spatial inequities in the Aotearoa health system, across a range of health services,[[29,45,46]] and provides additional context that may be relevant to recent findings of geographic variation in childhood immunisation rates.[[47]] It also highlights that even when new health services (such as COVID-19 vaccination services) are added to the health system there is no guarantee that they will be equitably distributed. If there is no clear planning, guidance, or monitoring for pro-equity service distributions, the result is inevitably inequitable access that compounds existing health inequities. Although health services are only one component of the social determinants that shape the distribution and equity of health outcomes, they are an aspect that health authorities are theoretically able to influence. Ensuring the fair distribution of health services, to improve access for populations with the highest health needs and risk of severe outcomes, is one action that health authorities can take to improve health equity in Aotearoa. It is becoming increasingly important that the Māori Health Authority and Health NZ monitor, and improve, the spatial equity of all health services in Aotearoa. These research findings emphasise the importance of and need for national strategies that make use of both geospatial and public health intelligence to guide a national vaccination rollout—and the equitable delivery of health services in general. As the health system reforms in Aotearoa, this research can inform approaches to monitor and improve the spatial equity of a wide range of health services.

The finding of significantly lower spatial access to COVID-19 vaccination services for communities with a higher proportion of Māori residents, and that more than a quarter of Māori live in areas with low access to vaccination services, indicates structural racism in Aotearoa New Zealand’s COVID-19 vaccination rollout. In combination with an age-based prioritisation for vaccinations that has held back a large proportion of the structurally younger Māori population,[[48]] and individual experiences of racism within the health system,[[12–15]] this has left a disproportionate number of Māori unvaccinated against COVID-19. International evidence indicates that geographic and ethnic targeting of vaccination services results in more equitable uptakes and avoids more deaths than age-based prioritisation alone.[[49]] This underlines that the COVID-19 vaccination rollout has failed to protect Māori, and reinforces the urgent need for an independent Māori Health Authority, with a service commissioning mandate, to design and deliver effective and equitable services for Māori.

The results also highlight significant variation in levels of access—and inequity of access between DHBs. This is not surprising, as localised decision-making around the delivery of COVID-19 vaccinations has been devolved from the Ministry of Health to DHBs, which are likely to have followed different vaccine rollout plans, had different levels of partnership with iwi, and relied on the existing distribution of health facilities—which already provide differing levels of access to services across DHBs. These differences in access and spatial equity between DHBs appears to be associated with the equity of vaccine uptake for Māori. As at 20 August 2021, Capital & Coast DHB had both the highest average level and most even distribution of spatial access to vaccination services, and high relative vaccination rates for Māori living in the region. Similarly, Southern DHB had high levels of average access to services, and the highest relative vaccination rate for Māori. On the other hand, DHBs which are providing low levels of spatial access to vaccination services, such as Lakes, Northland, Bay of Plenty and Whanganui, all had low vaccination rate ratios for Māori (0.48–0.52).

Improving the spatial equity of COVID-19 vaccination services, by offering additional services in areas with high priority populations and low access to current vaccination services, will be important for improving the equity of vaccination uptake and protecting priority populations. Previous research suggests that vaccinations delivered at schools would offer good access to 99.9% of the total population.[[18]] School-based vaccinations could contribute to a more equitable paediatric vaccine rollout, and may also reach as-yet-unvaccinated adults. While many rural and socio-economically constrained populations are at high risk of severe outcomes from COVID-19 infection,[[50]] the Ministry of Health has not at the time of writing reported vaccination rates according to area-level socio-economic deprivation, or rural-urban status. However, independent analysis suggests that the overall vaccination rollout for rural people is also inequitable.[[51]] While a flurry of additional vaccination sites has appeared since the start of the Delta outbreak in Aotearoa, ongoing monitoring suggests that access has not substantially improved in rural areas.[[52]] Additional research examining changes in spatial access and equity throughout the Delta outbreak is currently underway. Before Aotearoa can consider loosening international and internal border restrictions, or removing protective public health measures, it is essential to achieve high vaccination rates among priority populations who will experience the most severe health outcomes from COVID-19 infection.

Summary

Abstract

Aim

To examine the spatial equity, and associated health equity implications, of the geographic distribution of COVID-19 vaccination services in Aotearoa New Zealand.

Method

The distribution of Aotearoa’s population was mapped, and the enhanced two-step floating catchment method (E2SFCA) applied to estimate spatial access to vaccination services. The Gini coefficient and spatial autocorrelation measures assessed the spatial equity of vaccination services. Additional statistics included an analysis of spatial accessibility for priority populations, and by District Health Board (DHB) region.

Results

Spatial 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, Pasifika, and older people have 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 DHB region as does the Gini coefficient, 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.

Author Information

Jesse Whitehead: Te Ngira: Institute for Population Research (formerly NIDEA), University of Waikato, Hamilton, New Zealand. Polly Atatoa Carr: Te Ngira: Institute for Population Research (formerly NIDEA), University of Waikato, Hamilton, New Zealand; Waikato District Health Board, Hamilton, New Zealand. Nina Scott: Waikato District Health Board, Hamilton, New Zealand. Ross Lawrenson: Waikato District Health Board, Hamilton, New Zealand; Waikato Medical Research Group, University of Waikato, Hamilton, New Zealand.

Acknowledgements

Correspondence

Jesse Whitehead, University of Waikato, Gate 1 Knighton Road, Hamilton New Zealand, +64 7 838 4040 (phone), +64 7 838 4621 (fax).

Correspondence Email

jesse.whitehead@waikato.ac.nz

Competing Interests

Nil.

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Aotearoa New Zealand’s (hereafter Aotearoa) management strategy against COVID-19 put the country in a good position internationally with relatively few deaths or active COVID-19 cases for most of 2020 and 2021.[[1]] The Government’s vaccination delivery programme has become increasingly important to save morbidity and mortality. The community outbreak of the Delta variant of COVID-19 on 17 August 2021 highlights that, until the vaccination rollout is complete, there is a continued risk. Achieving the equitable and universal delivery of a vaccine is therefore essential to help protect all residents of Aotearoa, and particularly priority populations who are at greatest risk of risk of infection, and most vulnerable to COVID-19 severity. Achieving equitable health outcomes means prioritising some populations with better access and resourcing.[[2]]

In its vaccination rollout[[3,4]] (see Text Box 1) the Government has prioritised border and MIQ workers, frontline healthcare workers, older people, and those with ‘relevant’ underlying health conditions. However, internationally, arguments have been made for the allocation of COVID-19 vaccines according to not only individual risk, but also social vulnerabilities—such as socio-economic status, occupation, housing and living conditions, ethnicity, and other factors that limit access to healthcare.[[5]] Indigenous populations must also be prioritised.[[6]] The health impact of COVID-19 is likely to be higher among Māori and other Indigenous populations.[[7,8]] There are stark, persistent, and increasing health inequities in Aotearoa experienced particularly by Indigenous Māori, that occur across the life course and are well documented.[[2,9,10]] Māori are disproportionately impacted by poorer access to the social determinants of health, including housing, quality healthcare,[[11]] and racism in the health system and wider society.[[12–15]]

Achieving equitable immunisation necessarily involves balancing the logistical constraints of distributing and administering the time and temperature sensitive COVID-19 vaccine, with minimising barriers for those who wish to receive it. There are various ways of conceptualising ‘fairness’ and prioritising vaccine delivery,[[5,16]] which in turn can have different impacts on COVID-19 related deaths, hospitalisations, and ICU admissions.[[17]] A major priority should be to immunise people who might otherwise die if they contract COVID-19, while a secondary aim is to reduce admissions to hospital and to protect the health system. In this paper, priority populations therefore include Māori, Pasifika, people aged 65 and over, people with comorbidities and those living in areas of high socio-economic deprivation.[[18]] As noted, the vaccine rollout in Aotearoa has taken a phased approach, grouping populations according to priority and risk.[[19]] View Text Box 1.

The Pfizer vaccine has been offered across Aotearoa at a range of locations acting as vaccination services, including some general practitioner (GP) clinics and pharmacies. It has also been offered at a range of new ‘pop-up’ clinics at sports grounds, marae, and stadium mega-clinics.[[20]] Decision-making and the implementation of the vaccine rollout has been devolved to District Health Boards (DHBs) who are responsible for the health of the populations in their region.

Spatial accessibility and spatial equity

The racialised inequitable access to and uptake of COVID-19 vaccination seen internationally,[[5,21,22]] could occur in Aotearoa, where access to healthcare is inequitable.[[23–25]] Additional barriers to accessing healthcare, particularly for Māori, include the (in)appropriateness, (un)availability, (in)acceptability and poorer quality care provided by many services.[[26–29]] Māori and Pasifika people report experiencing racism from healthcare providers,[[12–15]] and are disproportionately affected by cost and transport as barriers to accessing GP services.[[30]] Barriers to vaccine access that disproportionately affect priority populations—with the most risk of COVID-19 severity—will exacerbate key inequities. Health authorities should aim for an equitable and universal vaccine rollout which ensures spatial equity—giving priority populations appropriately higher access to vaccination services and opportunities for vaccination. This paper examines the spatial equity of the vaccine rollout in Aotearoa with a particular focus on priority populations.

Methodology

Key steps

Four key steps were taken in the assessment of the spatial equity of COVID-19 vaccination services.

Figure 1: Key steps in assessing the spatial equity of COVID-19 vaccination services.

Data gathering

The population data is based on 2018 census data at the Statistical Area 1 (SA1) level, which includes information on the usually resident population, age, and Ethnicity of Residents in each SA1.[[31]] The population aged 15 and over was used to represent the ‘vaccine eligible’ population at the time of analysis. Socio-economic constraint was estimated with the 2018 New Zealand Index of Socioeconomic Deprivation (NZDep18).[[32]] The Geographic Classification for Health (GCH)[[33]] was used to define rural and urban areas of Aotearoa. Travel times were estimated using Beere’s road network layer.[[34]] COVID-19 vaccination services locations were downloaded on 18 August 2021 from the Healthpoint[[20]] website. Vaccination services were linked to the Ministry of Health Facilities dataset,[[35]] which includes XY coordinates for all health facilities in Aotearoa. Since no service volume data were available it was assumed in all calculations that service volume is equal at all sites.

Spatial accessibility

Geographic Information Systems (GIS) were used to quantify the spatial equity of COVID-19 vaccination services. The three steps to spatial equity analysis involve defining, estimating and quantifying spatial equity.[[36]] Spatial equity usually refers to a fair distribution of resources relative to need.[[37]] In order to achieve equitable health outcomes, some populations should be prioritised and have better access to services.[[2]] Floating Catchment Area (FCA) techniques estimate accessibility by considering service availability relative to population size and the distance between populations and services to produce an accessibility score for each small area unit within a study area. This paper applied the enhanced two-step floating catchment area method (E2SFCA)[[38]] to estimate accessibility to COVID-19 vaccination services in Aotearoa, using the 30-minute drivetime catchments originally proposed.[[39]]

Spatial equity

Once overall levels of accessibility have been estimated, the Gini coefficient can be used to quantify equality. The Gini coefficient assesses the distribution of resources (such as income, or in this case, accessibility) across a population, and provides an equality score between zero and one, with zero representing a perfectly equal distribution and one indicating a completely unequal distribution.[[40]] To examine the equality of spatial access to COVID-19 vaccination services, the population weighted Gini coefficient was calculated in R.

Although the Gini coefficient gives an indication of whether the distribution of spatial accessibility to vaccination services is equal, it does not indicate whether such a distribution is equitable. For instance, in a system where the entire vaccine eligible population has the same level of access to vaccination services, access would be inequitable for priority populations. Therefore, it is important to examine which locations and populations have high or low levels of access to services. The presence of statistically significant clustering of spatial accessibility scores was tested using Global Moran’s I measure of spatial autocorrelation. Anselin’s Local Indicator of Spatial Autocorrelation Moran’s I (LISA) was also calculated to map the locations of statistically significant clusters of high and low access.

Additional statistical analysis

Additional statistical tests were undertaken to determine whether spatial access to vaccination services varied for priority populations—particularly for Māori, Pasifika, older people, and those living in areas of high socio-economic deprivation. Differences in spatial access to vaccination services between rural and urban areas of Aotearoa were also examined. To establish whether median spatial accessibility scores, as estimated by the E2SFCA, vary significantly for different population groups, Mann-Whitney tests were performed. A Kurskal-Wallis test and Mann-Whitney test were also used to determine whether there was a statistically significant difference in the median spatial accessibility scores for each DHB region. The proportion of each priority population group living in areas with poor vaccination access was calculated for each DHB region.

Results

Spatial accessibility

In total 447 vaccination services were identified, of which 212 (47%) were GP clinics, 91 (20%) were pharmacies, 50 (11%) appeared to be DHB-run dedicated vaccination centres, and 28 (6%) appeared to be iwi led, or run by Māori or Pasifika providers. Figure 2 shows the locations of these vaccination services and indicates the geographic distribution of spatial accessibility scores across Aotearoa. Scores were sorted into quintiles, with Quintile 1 (Q1—best access) represented in light red and Quintile 5 (Q5—worst access) in dark red. While access to COVID-19 vaccination services in large cities is generally good, there are large parts of rural Aotearoa with poor access. Of the major centres, Ōtautahi appears to have the worst access, while Te Whanganui-a-Tara and Ōtepoti have good levels of access to vaccination clinics. View Figure 2.

Spatial equity

Gini coefficient

A Gini coefficient of 0.426 was calculated, suggesting an unequal distribution of vaccination services.

Spatial autocorrelation

Global Moran’s I returned a statistically significant result (I=0.349, p<0.00), indicating that spatial accessibility scores were clustered. The LISA analysis results (Figure 3) indicate where those clusters are. Dark green represents high-high clusters, which are statistically significant clusters of areas of high accessibility surrounded by other high access areas. Areas in light green are high-low outliers, which have high accessibility but are surrounded by areas with low access. Similarly, the dark blue regions represent low-low clusters, while light blue areas are low-high outliers. Clusters of high accessibility tend to be in major cities, while rural and remote areas of Aotearoa have clusters of poor access to vaccination services. View Figure 3.

Additional statistical analysis

Further statistical analysis indicates that differences in access to vaccination services negatively affect priority populations, and are therefore inequitable. Table 1 displays the median spatial accessibility scores of different types of neighbourhoods. Higher spatial accessibility scores indicate better spatial access to vaccination services. Spatial accessibility scores across Aotearoa ranged from 0.0 to 382.4, with an average score of 13.6, a median score of 11.1, and an interquartile range (IQR) of 12.2. View Table 1.

Mann-Whitney tests revealed statistically significant differences in the median spatial accessibility scores of some types of neighbourhoods. Areas with a higher proportion of Māori residents (>15%) had statistically significantly worse access to vaccination services than neighbourhoods with a lower proportion of Māori residents (p<.001). Access to vaccination services was also worse in neighbourhoods with a high proportion of Pasifika residents (>8%) compared to areas with a low proportion of Pasifika residents (p<.001). Similarly, neighbourhoods with a higher proportion of over 65-year-olds (>15%) had worse access to vaccine services than areas with a lower proportion of over 65-year-olds (p<.001). Rural residents also had worse access to vaccination services than residents of urban areas (p<.001). A Kruskal-Wallis rank sum test also revealed a statistically significant difference between accessibility scores across the five quintiles of socio-economic deprivation. Neighbourhoods with high levels of socio-economic deprivation had higher median access scores than neighbourhoods in NZDep18 quintiles 1–4 (p<.001).

A statistically significant difference between median DHB levels of spatial accessibility was determined by a Kruskal-Wallis rank sum test (H[[2]]=17643.3, p<.001). Table 2 shows, for each DHB region, the median spatial accessibility score, Gini coefficient, and the proportion of each priority population group (and total eligible population) living in an area with poor spatial access (Q5) to vaccination services. Table 2 also displays vaccination rate ratios for Māori and Pasifika residents of each DHB region, indicating the relative proportion of Māori and Pasifika people who have received two vaccine doses, as compared to non-Māori and non-Pasifika residents. DHBs with higher levels of average spatial accessibility appear to have more equitable vaccine uptake for Māori and Pasifika people. A strong and statistically significant correlation was identified between DHBs’ median levels of spatial accessibility and vaccination rate ratios for Māori (r=.69, p<.001) but not Pasifika (r=.36, p=.112) as at 20 August 2021. The median DHB levels of spatial accessibility (estimated in this paper at 18 August 2021) continued to be associated with vaccination rate ratios for Māori on 6 November 2021, with a moderate correlation identified (r=0.47, p<0.05). Strong and statistically significant negative relationships were also identified between the proportion of Māori living in areas of low spatial access to vaccination services, and the vaccination rate ratios for Māori at both 20 August 2021 (r=-.68, p<.001) and 6 November 2021 (r=-.60, p<.01). This indicates that DHB regions with a higher proportion of Māori living in areas with poor access to vaccination services are likely to also have more inequitable vaccination uptake, with lower rates for Māori than non-Māori residents. Weak and non-significant correlations were identified between DHBs’ Gini coefficients and vaccination rate ratios for Māori (r=-.08, p=.75) and Pacific (r=-.15, p=.52). View Table 2.

Discussion

This work has some limitations. The E2SFCA uses drive-time-based catchments to calculate spatial accessibility to services. One key limitation of this approach is the inherent assumption that all residents of an SA1 have access to a private vehicle (with a current warrant of fitness) and are able to afford petrol. Residents in neighbourhoods with higher levels of socio-economic deprivation (who are disproportionately Māori and Pasifika) are less likely to have access to a motor vehicle or be able to cover additional or unplanned transportation costs. Likewise, the E2SFCA does not assess the wider, non-spatial, domains of access. Vaccination services listed on the Healthpoint website are likely to be accurate and reflective of the actual services available on 18 August 2021, but will not reflect additional clinics that have been added in response to the COVID-19 Delta variant outbreak. This analysis does not include any vaccination services that are not listed on the Healthpoint website. No information was available on the capacity of vaccination services, the availability of appointments, or the different service models that may have been used by vaccination services. This may have resulted in an underestimate of accessibility in some urban areas, and an overestimate of accessibility in some rural areas—potentially further exacerbating inequities in vaccination accessibility. While data availability and quality is beyond the control and scope of this paper, it highlights the importance of strong public health intelligence, including the collection and maintenance of information on service delivery. Issues with the implementation of the 2018 census[[42]] mean that the quality of the ethnicity variable has been independently rated as ‘moderate’.[[43]] Additionally, other census variables may have impacted on the quality of NZDep18. Furthermore, ethnicity data in the 2018 census are not prioritised, so individuals who report multiple ethnicities are counted more than once.[[44]] Therefore the results presented in this paper are population estimates using the best available data.

Despite these limitations, this analysis indicates that, as predicted previously,[[18]] spatial access to vaccination services across Aotearoa is inequitable. Māori, Pasifika people, over 65-year-olds, and rural residents have worse access to vaccination services. Given the higher burden of disease, and increased likelihood of severe COVID-19 infection outcomes in these groups, priority populations must have opportunities to become vaccinated as soon as possible. Health authorities have had opportunities to work with priority communities to ensure an equitable vaccination rollout. Vaccination services locations could have been proactively planned to target priority populations and maximise access opportunities for these groups. The fact that more than two-thirds of vaccination services were run from health facilities such as GP clinics, pharmacies, and hospitals suggest that authorities have relied on current health services, regardless of their inequitable distribution already highlighted in the research literature.[[18,25,29]] This decision appears to have resulted in a disproportionately poor access to COVID-19 vaccination for older people, Māori, Pasifika, and rural people, all groups who are at risk of severe outcomes from COVID-19 infection.

These findings add to the body of research describing spatial inequities in the Aotearoa health system, across a range of health services,[[29,45,46]] and provides additional context that may be relevant to recent findings of geographic variation in childhood immunisation rates.[[47]] It also highlights that even when new health services (such as COVID-19 vaccination services) are added to the health system there is no guarantee that they will be equitably distributed. If there is no clear planning, guidance, or monitoring for pro-equity service distributions, the result is inevitably inequitable access that compounds existing health inequities. Although health services are only one component of the social determinants that shape the distribution and equity of health outcomes, they are an aspect that health authorities are theoretically able to influence. Ensuring the fair distribution of health services, to improve access for populations with the highest health needs and risk of severe outcomes, is one action that health authorities can take to improve health equity in Aotearoa. It is becoming increasingly important that the Māori Health Authority and Health NZ monitor, and improve, the spatial equity of all health services in Aotearoa. These research findings emphasise the importance of and need for national strategies that make use of both geospatial and public health intelligence to guide a national vaccination rollout—and the equitable delivery of health services in general. As the health system reforms in Aotearoa, this research can inform approaches to monitor and improve the spatial equity of a wide range of health services.

The finding of significantly lower spatial access to COVID-19 vaccination services for communities with a higher proportion of Māori residents, and that more than a quarter of Māori live in areas with low access to vaccination services, indicates structural racism in Aotearoa New Zealand’s COVID-19 vaccination rollout. In combination with an age-based prioritisation for vaccinations that has held back a large proportion of the structurally younger Māori population,[[48]] and individual experiences of racism within the health system,[[12–15]] this has left a disproportionate number of Māori unvaccinated against COVID-19. International evidence indicates that geographic and ethnic targeting of vaccination services results in more equitable uptakes and avoids more deaths than age-based prioritisation alone.[[49]] This underlines that the COVID-19 vaccination rollout has failed to protect Māori, and reinforces the urgent need for an independent Māori Health Authority, with a service commissioning mandate, to design and deliver effective and equitable services for Māori.

The results also highlight significant variation in levels of access—and inequity of access between DHBs. This is not surprising, as localised decision-making around the delivery of COVID-19 vaccinations has been devolved from the Ministry of Health to DHBs, which are likely to have followed different vaccine rollout plans, had different levels of partnership with iwi, and relied on the existing distribution of health facilities—which already provide differing levels of access to services across DHBs. These differences in access and spatial equity between DHBs appears to be associated with the equity of vaccine uptake for Māori. As at 20 August 2021, Capital & Coast DHB had both the highest average level and most even distribution of spatial access to vaccination services, and high relative vaccination rates for Māori living in the region. Similarly, Southern DHB had high levels of average access to services, and the highest relative vaccination rate for Māori. On the other hand, DHBs which are providing low levels of spatial access to vaccination services, such as Lakes, Northland, Bay of Plenty and Whanganui, all had low vaccination rate ratios for Māori (0.48–0.52).

Improving the spatial equity of COVID-19 vaccination services, by offering additional services in areas with high priority populations and low access to current vaccination services, will be important for improving the equity of vaccination uptake and protecting priority populations. Previous research suggests that vaccinations delivered at schools would offer good access to 99.9% of the total population.[[18]] School-based vaccinations could contribute to a more equitable paediatric vaccine rollout, and may also reach as-yet-unvaccinated adults. While many rural and socio-economically constrained populations are at high risk of severe outcomes from COVID-19 infection,[[50]] the Ministry of Health has not at the time of writing reported vaccination rates according to area-level socio-economic deprivation, or rural-urban status. However, independent analysis suggests that the overall vaccination rollout for rural people is also inequitable.[[51]] While a flurry of additional vaccination sites has appeared since the start of the Delta outbreak in Aotearoa, ongoing monitoring suggests that access has not substantially improved in rural areas.[[52]] Additional research examining changes in spatial access and equity throughout the Delta outbreak is currently underway. Before Aotearoa can consider loosening international and internal border restrictions, or removing protective public health measures, it is essential to achieve high vaccination rates among priority populations who will experience the most severe health outcomes from COVID-19 infection.

Summary

Abstract

Aim

To examine the spatial equity, and associated health equity implications, of the geographic distribution of COVID-19 vaccination services in Aotearoa New Zealand.

Method

The distribution of Aotearoa’s population was mapped, and the enhanced two-step floating catchment method (E2SFCA) applied to estimate spatial access to vaccination services. The Gini coefficient and spatial autocorrelation measures assessed the spatial equity of vaccination services. Additional statistics included an analysis of spatial accessibility for priority populations, and by District Health Board (DHB) region.

Results

Spatial 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, Pasifika, and older people have 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 DHB region as does the Gini coefficient, 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.

Author Information

Jesse Whitehead: Te Ngira: Institute for Population Research (formerly NIDEA), University of Waikato, Hamilton, New Zealand. Polly Atatoa Carr: Te Ngira: Institute for Population Research (formerly NIDEA), University of Waikato, Hamilton, New Zealand; Waikato District Health Board, Hamilton, New Zealand. Nina Scott: Waikato District Health Board, Hamilton, New Zealand. Ross Lawrenson: Waikato District Health Board, Hamilton, New Zealand; Waikato Medical Research Group, University of Waikato, Hamilton, New Zealand.

Acknowledgements

Correspondence

Jesse Whitehead, University of Waikato, Gate 1 Knighton Road, Hamilton New Zealand, +64 7 838 4040 (phone), +64 7 838 4621 (fax).

Correspondence Email

jesse.whitehead@waikato.ac.nz

Competing Interests

Nil.

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