Proportional mortality during the 1918 influenza pandemic in Alaska

During the 1918 influenza pandemic, social and biological factors combined to create a marked heterogeneity of disease burden within populations. Alaska, then a territory of the United States, shows particularly striking mortality diversity, with Indigenous populations of Alaska Natives suffering higher mortality than their non-Indigenous counterparts. This study expands on baseline knowledge of mortality within Alaska territory and introduces mortality rates by indigenous status and sex. All available death certificates recorded in Alaska between 1915-1921 (n=7,147) were analyzed. Mortality rates were calculated using population estimates from the 1910 and 1920 United States census reports. A multilinear regression analysis was used to determine the impact of Indigenous status and sex on pneumonia and influenza deaths during the pandemic. Death counts show that Alaska Natives mortality from pneumonia and influenza were 3.4 times higher than non-Alaska Natives. Correcting for population size, proportional deaths were 4 times higher among Alaska Natives averaged throughout the pandemic and 6 times higher among Alaska Natives during the height of the pandemic in 1918. There were little sex-based differences in mortality in either Alaska Native or non-Alaska Native populations. These findings reinforce the importance of incorporating sociocultural analyses into pandemic mortality studies and highlight the need for increased understanding of the impact of Indigenous populations during disease events.