Examining spatial variation and inequity in COVID-19 immunisation coverage in Aotearoa New Zealand: a nationwide geospatial study

Abstract

Background: Aotearoa New Zealand (NZ) was almost unique worldwide in having very limited community transmission of COVID-19 prior to March 2022. Using nationwide data, we examined variation in COVID-19 immunisation coverage in adults in 2022, when NZ transitioned from elimination to mitigation in a largely infection-naïve population.

Method: We used the COVID-19 Immunisation Register (CIR) within the Integrated Data Infrastructure (IDI) to calculate immunisation coverage among adults aged 18 years and over between 1st January and 31st December 2022 by age, ethnicity and residential address. Geospatial analyses were undertaken in ArcGIS Pro.

Results: Among adults >65 years, between January and March 2022, when widespread community transmission of COVID-19 began, uptake of third doses increased for European ethnicity by 7.9 %, reaching 87.0 % by December 2022 and by 18.5 % in Māori, 21.6 % in Pacific and 24.2 % in Asian people, reaching 80.7 %, 80.2 % and 83.5 % by December. In contrast, the proportion of adults >65 years of any ethnicity who had received zero doses by January 2022 remained stable from 6.3 % (Asian) to 10.8 % (Māori), with less than 0.15 % receiving any doses by December. Third dose uptake was lowest and zero doses highest in adults of all ages living in the most deprived and among Māori and Pacific people. Among Asian people, the proportion zero dose was highest >65 years, whereas in other ethnic groups it was highest in younger adults. There was significant spatial variation by area with a greater proportion of zero-dose populations in more rural areas.

Conclusion: Our study is among the first internationally to examine patterns of non-receipt of COVID-19 vaccines and differences in age-related coverage by sociodemographic factors which have implications for tailored communication and community engagement.