A retrospective epidemiologic analysis of influenza pandemics in Arkansas

The purpose of this study is to compare and contrast influenza mortality in Arkansas during the pandemics of: 1918 (aka Spanish flu), 1957, 1968, and 2009 (H1N1, aka Swine flu). Death certificate and U.S. census data were gathered and analyzed for statistical differences in mortalities based on sex, age, and geographic regions of Arkansas for each pandemic-the geographic regions were defined by the five Public Health Units classified by the Arkansas Department of Health. Regional mortalities were also analyzed across all pandemics to investigate how the different pandemic influenza A viruses affected each individual region. It was hypothesized that males presented higher mortalities than females and the more rural regions exhibited higher proportional mortalities than the urbanized regions. It was believed the young and old populations presented higher mortalities for the pandemics, with the exceptions of the two H1N1 viruses. It was hypothesized that these pandemics presented higher mortalities in the young adult and middle-age groups. Chi-square analyses for each pandemic showed only the 1918 pandemic had statistical differences between male and female mortalities (p0.5). Data showed the more urban regions sustained higher proportional mortalities than the rural regions. Over the course of the century, the four pandemics resulted in decreased mortalities throughout the state. Regional mortality rates offer a suggestion as to which areas or regions to focus increased public health efforts during future influenza outbreaks in Arkansas. With this knowledge, health professionals may be able to distribute response resources efficiently to reduce mortality rates of future pandemics