Updating the Accounts: Global Mortality of the 1918-1920 "Spanish" Influenza Pandemic

TLDR

The 1918‑20 influenza pandemic unfolded in three waves, but mortality data are likely underreported due to nonregistration, missing records, misdiagnosis, and variable local reporting. This paper estimates the global mortality to be around 50 million. The study proposes a global mortality estimate of about 50 million, higher than the 24.7–39.3 million range from earlier revisions.

Abstract

The influenza pandemic of 1918-20 is recognized as having generally taken place in three waves, starting in the northern spring and summer of 1918. This pattern of three waves, however, was not universal: in some locations influenza seems to have persisted into or returned in 1920. The recorded statistics of influenza morbidity and mortality are likely to be a significant understatement. Limitations of these data can include nonregistration, missing records, misdiagnosis, and nonmedical certification, and may also vary greatly between locations. Further research has seen the consistent upward revision of the estimated global mortality of the pandemic, which a 1920s calculation put in the vicinity of 21.5 million. A 1991 paper revised the mortality as being in the range 24.7-39.3 million. This paper suggests that it was of the order of 50 million. However, it must be acknowledged that even this vast figure may be substantially lower than the real toll, perhaps as much as 100 percent understated.