A comparative study of the 1918–1920 influenza pandemic in Japan, USA and UK: mortality impact and implications for pandemic planning

• Published in: Epidemiology and infection Vol. 137; no. 8; pp. 1062 - 1072
• Main Authors: RICHARD, S. A., SUGAYA, N., SIMONSEN, L., MILLER, M. A., VIBOUD, C.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.08.2009
• Subjects: Age; Age Distribution; Age groups; Age patterns; Biological and medical sciences; Death; Disease Outbreaks - history; Epidemics; excess mortality; Fundamental and applied biological sciences. Psychology; geography; History, 20th Century; Humans; influenza; Influenza Pandemics; Influenza, Human - history; Influenza, Human - mortality; Japan - epidemiology; Microbiology; Mortality; pandemic; Pandemics; Pneumonia; Prefectures; United Kingdom - epidemiology; United States - epidemiology; Viruses; Young adults; Asia; Japan; British Isles; USA; influenza; excess mortality; pandemic; geography; Age patterns; Infection; Human; Microbiology; Viral disease; Influenza; Epidemiology; Comparative study
• ISSN: 0950-2688; 1469-4409
• DOI: 10.1017/S0950268809002088

Historical studies of influenza pandemics can provide insight into transmission and mortality patterns, and may aid in planning for a future pandemic. Here, we analyse historical vital statistics and quantify the age-specific mortality patterns associated with the 1918–1920 influenza pandemic in Japan, USA, and UK. All three countries showed highly elevated mortality risk in young adults relative to surrounding non-pandemic years. By contrast, the risk of death was low in the very young and very old. In Japan, the overall mortality impact was not limited to winter 1918–1919, and continued during winter 1919–1920. Mortality impact varied as much as threefold across the 47 Japanese prefectures, and differences in baseline mortality, population demographics, and density explained a small fraction of these variations. Our study highlights important geographical variations in timing and mortality impact of historical pandemics, in particular between the Eastern and Western hemispheres. In a future pandemic, vaccination in one region could save lives even months after the emergence of a pandemic virus in another region.