Differential mortality rates by ethnicity in 3 influenza pandemics over a century, New Zealand

Abstract

Evidence suggests that indigenous populations have suffered disproportionately from past influenza pandemics. To examine any such patterns for Māori in New Zealand, we searched the literature and performed new analyses by using additional datasets. The Māori death rate in the 1918 pandemic (4,230/100,000 population) was 7.3× the European rate. In the 1957 pandemic, the Māori death rate (40/100,000) was 6.2× the European rate. In the 2009 pandemic, the Māori rate was higher than the European rate (rate ratio 2.6, 95% confidence interval 1.3-5.3). These findings suggest some decline in pandemic-related ethnic inequalities in death rates over the past century. Nevertheless, the persistent excess in adverse outcomes for Māori, and for Pacific persons residing in New Zealand, highlights the need for improved public health responses.

Figure 1

Māori military personnel (Pioneer Battalion) performing the haka for New Zealand Cabinet Minister Sir Joseph Ward (at Bois de Warnimont, France, June 30, 1918). Photograph taken by Henry Armytage Sanders; from Alexander Turnbull Library, Timeframes: New Zealand and the Pacific through images; reference no. 1/2-013283-G (http://timeframes.natlib.govt.nz).

Figure 2

Mortality rate ratios (age-standardized on the basis of 2009 data) for Māori versus European/other New Zealanders (non-Māori/non-Pacific) during 3 influenza pandemics in New Zealand. *Data from (6); †official mortality rate data; ‡age-standardized to the Māori population. Error bar represents 95% CI.