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Volume 18, Number 1—January 2012

Historical Review

Differential Mortality Rates by Ethnicity in 3 Influenza Pandemics Over a Century, New Zealand

Nick WilsonComments to Author , Lucy Telfar Barnard, Jennifer A. Summers, G. Dennis Shanks, and Michael G. Baker
Author affiliations: University of Otago, Wellington, New Zealand (N. Wilson, L. Telfar Barnard, J.A. Summers, M.G. Baker); Australian Army Malaria Institute, Enoggera, Queensland, Australia (G.D. Shanks)

Main Article


Comparison of mortality rates for Māori versus non-Māori/European residents of New Zealand during multiple influenza pandemics*

Pandemic and data source Mortality rate
Comments (see Methods for details)
Māori Non-Māori Ratio†
1890s pandemic
Individual mortality data in
BDM database (10) Unknown (deaths not registered) 9.1% increase in deaths for 1890–94 compared with 1885–89 Based on comparison of no. deaths for top 10 surnames (see method used for 1957 pandemic). Official data also suggest increased influenza deaths for the 1890s beginning in 1890 (17).
1918–19 pandemic
National mortality data,
second wave (6), n = 8,573
deaths 4,230/100,000 population 580/100,000 population) (European) 7.3 See limitations with data quality described in the main text. Comparison was not age-standardized.
Mortality in New Zealand
military personnel, second
and third waves,‡ n = 1,113 2,501/100,000 population 1,103/100,000 population (European/ other) 2.3 (1.6–3.1)§ New Zealand military personnel of Pacific peoples ethnicity also had a raised mortality rate, but absolute number of deaths was small (n = 12) and difference was not significant.
1957 pandemic
National mortality data for
Asian influenza pandemic,
official report (11), n = 179
deaths 39.6/100,000 population 6.4 per 100,000 population (European) 6.2 Of note, at this time surveillance systems were crude, and attention to quality ethnicity coding was not robust. There was no widespread use of vaccination in response to this pandemic in New Zealand.
Individual mortality data in
BDM database for selected
surnames (10), n = 38
deaths in Aug/Sep 1957 49.0% increase for Aug/Sep 1957 compared with same period in 1956 and 1958 Whole New Zealand population: 20.3% increase 2.4 (Māori vs. total population) See Discussion for limitations with this method.
2009 pandemic¶
All cases with pandemic
(H1N1) 2009 as primary
cause of death,# n = 49 2.0 (0.8–3.1)§ 0.8 (0.5–1.1)§ 2.6 (1.3–5.3)§ For Pacific peoples in New Zealand, rate = 4.6 (2.0–7.2)§

*BDM, Births, Deaths & Marriages.
†Māori:non-Māori except as indicated.
‡Age standardization was not possible with available data; 1 study reported that Māori and European soldiers had similar median ages of 24 and 26 years, respectively (8).
§Values in parentheses are 95% confidence intervals.
¶Jun–Sep 2009. Cumulative age-standardized mortality rates per 100,000 population, age-standardized to Māori population. Ratio is Māori versus other New Zealanders (non-Māori and non-Pacific, mainly European).
#Identified by Mortality Review Group.

Main Article