and protracted prostration led to hysteria, melancholia, and insanity with suicidal intent” (Jordon, 1927:265).

The 1918 virus also targeted young adults. In South African cities, those between the ages of 20 and 40 accounted for 60 percent of the deaths (Katzenellenbogen, 1988). In Chicago the deaths among those aged 20 to 40 nearly quintupled deaths of those aged 41 to 60 (Van Hartesveldt, 1992). A Swiss physician “saw no severe case in anyone over 50.”1 In the “registration area” of the United States—those states and cities that kept reliable statistics—the single greatest number of deaths occurred in the cohort aged 25 to 29, the second greatest in those aged 30 to 34, and the third in those aged 20 to 24. More people died in each one of those 5-year groups than the total deaths among all those over age 60, and the combined deaths of those aged 20 to 34 more than doubled the deaths of all those over 50 (U.S. Bureau of the Census, 1921). The single group most likely to die if infected were pregnant women. In 13 studies of hospitalized pregnant women during the 1918 pandemic, the death rate ranged from 23 to 71 percent (Jordon, 1927:273). Of the pregnant women who survived, 26 percent lost the child (Harris, 1919). (As far back as 1557, people connected influenza with miscarriage and the death of pregnant women.)

The case mortality rate varied widely. An overall figure is impossible to obtain, or even estimate reliably, because no solid information about total cases exists. In U.S. Army camps where reasonably reliable statistics were kept, case mortality often exceeded 5 percent, and in some circumstances exceeded 10 percent. In the British Army in India, case mortality for white troops was 9.6 percent, for Indian troops 21.9 percent.

In isolated human populations, the virus killed at even higher rates. In the Fiji islands, it killed 14 percent of the entire population in 16 days. In Labrador and Alaska, it killed at least one-third of the entire native population (Jordan, 1927; Rice, 1988).

But perhaps most disturbing and most relevant for today is the fact that a significant minority—and in some subgroups of the population a majority—of deaths came directly from the virus, not from secondary bacterial pneumonias.

In 1918, pathologists were intimately familiar with the condition of lungs of victims of bacterial pneumonia at autopsy. But the viral pneumonias caused by the influenza pandemic were so violent that many investigators said the only lungs they had seen that resembled them were from victims of poison gas.


Correspondenz-Blatt fur Schweizer Aerzte, Basel, 11/5/18. 48, #40, “influenza epidemic,” E. bircher, p. 1338, quoted in JAMA 71(23):1946.

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