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

Abstract

SUMMARYHistorical 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.

The 1918 influenza pandemic and subsequent birth deficit in Japan

“…The plot shows two exceptional peaks in deaths during this period, one in November 1918 and the other in January 1920. This pattern is consistent with the findings from previous research that Japan experienced two major waves of pandemic-associated mortality, with the first wave being the more severe of the two (Richard et al 2009). More importantly for the purpose this study, a trough in births occurred in August 1919, nine months after pandemic-associated mortality peaked in November 1918.…”

“…The pandemic also caused an excess of stillbirths in Japan (Nishiura 2009). In a pattern similar to that of its colony, Taiwan (Chandra and Yu, 2015), Japan experienced two major waves of mortality during the pandemic, the first between October 1918 and February 1919 with a peak in November 1918, and the second between October 1919 and February 1920 with a peak in January 1920 (Ding 2008;Richard et al 2009). According to official reports from the Japanese Sanitary Bureau, a total of over 19.2 million infected cases were reported during the first outbreak, resulting in over 204,000 deaths and a death rate of approximately 1.06% (Central Sanitary Bureau 1920).…”

Verification of the Overestimation of the “Deaths Associated with Influenza Pandemic of 1918–1919, Japan” Claimed in a Demographic Study

“…This new estimate is 8 times greater than that of the official records based on the surveillance during that time, which had been accepted broadly: 257 thousand deaths from August 1918 to July 1919, which included the first wave that started in the October 1918 and peaked in the November 1918, and 128 thousand deaths from August 1919 to July 1920, which included the second wave that started from December 1919 and peaked in January 1920 (8). It is much greater than the figure of 453 thousand deaths estimated by Hayami (9), and 4 times greater than the latest estimate suggested by Richard et al, which had been the largest estimate until Chandra's report: 481 thousand deaths as a total of the first and second waves (10). We think that Chandra's preconception was not sound from the socio-historical and epidemiological viewpoints, and that the calculation and its interpretation were misleading.…”

“…The number is at least 0.2 million, according to the Japanese authority's data (8), or beyond that, as previously reported (9,10). Consequently, the author's estimate should become further inflated to at least to 2.2 million or more than that, which would be also an unrealistic figure.…”

Todesfälle durch Influenzapandemien in Deutschland 1918 bis 2009

“…In den USA wurde z. B. eine Exzess-Mortalität zwischen 280 pro 100.000 Einwohner [26] und bis zu 650 pro 100.000 Einwohner [27] geschätzt, in Großbritannien von 590 pro 100.000 [26] und in Gesamteuropa von 1100 pro 100.000 [22] …”