Examining spatial variation for immunisation coverage in pregnant women: A nationwide and geospatial retrospective cohort study in Aotearoa New Zealand

M Hobbs; L Marek; A Young; E Willing; P Dawson; P McIntyre

doi:10.1016/j.socscimed.2023.116228

Examining spatial variation for immunisation coverage in pregnant women: A nationwide and geospatial retrospective cohort study in Aotearoa New Zealand

Soc Sci Med. 2023 Oct:335:116228. doi: 10.1016/j.socscimed.2023.116228. Epub 2023 Sep 12.

Authors

M Hobbs¹, L Marek², A Young³, E Willing⁴, P Dawson⁵, P McIntyre⁵

Affiliations

¹ Faculty of Health, Te Kaupeka Oranga, University of Canterbury, Te Whare Wānanga o Waitaha, Christchurch, Otautahi, Aotearoa, New Zealand; GeoHealth Laboratory, Te Taiwhenua o te Hauora, Geospatial Research Institute Toi Hangarau, University of Canterbury, Te Whare Wānanga o Waitaha, Christchurch, Otautahi, Aotearoa, New Zealand. Electronic address: matt.hobbs@canterbury.ac.nz.
² GeoHealth Laboratory, Te Taiwhenua o te Hauora, Geospatial Research Institute Toi Hangarau, University of Canterbury, Te Whare Wānanga o Waitaha, Christchurch, Otautahi, Aotearoa, New Zealand.
³ School of Pharmacy, He Rau Kawakawa, University of Otago, Te Whare Wānanga o Ōtākou, Dunedin, Ōtepoti, Aotearoa, New Zealand.
⁴ Kōhatu Centre for Hauora Maori I Division of Health Sciences I Te Whare Wānanga o Ōtākou, University of Otago I Dunedin, Aotearoa, New Zealand.
⁵ Women's & Children's Health, Dunedin School of Medicine, University of Otago, Te Whare Wānanga o Ōtākou, Dunedin, Ōtepoti, Aotearoa, New Zealand.

PMID: 37722144
DOI: 10.1016/j.socscimed.2023.116228

Abstract

Background: Maternal influenza and pertussis immunisation is crucial for protecting mothers during pregnancy and their babies in the first weeks of life against severe disease. We examined geospatial variation in maternal immunisation coverage among pregnant women in Aotearoa New Zealand and its health equity implications.

Method: We constructed a retrospective cohort including all pregnant women who delivered between 01 January 2013 and 31 December 2020 using administrative health datasets. Our outcomes were receipt of influenza or pertussis vaccine in any one of three relevant national databases (e.g. National Immunisation Register, Proclaims, or Pharmaceutical collection) during the eligible pregnancy.

Results: Data from our retrospective cohort study show significant regional variation in maternal immunisation coverage for both influenza and pertussis from 2013 to 2020. Maximal coverage was around 50% in the best performing regions, which means that half of the women who were pregnant (183,737 women) were not protected. In addition, we found significant spatio-temporal variation and clustering of immunisation coverage. Our findings are interactively available to explore here: https://geohealthlab.shinyapps.io/hapumama/ CONCLUSION: Our study is one of the first to examine spatial variation in maternal vaccination coverage in pregnant women at a national level over space and time. This provides powerful tools to measure the impact of interventions to improve coverage at national and regional levels, with specific reference to inequities between ethnic groups, likely applicable to similar settings internationally.

Keywords: Equity; Geographic information systems; Immunisation; New Zealand; Vaccine.