Between the autumn of 1918 and spring of the following year, 548,452 people died of the flu in America. The toll in Britain was 220,000, with similar numbers dead in France and Germany. No one knows the global toll, as records in the Third World were often poor, but it was not less than 20 million and probably more like 50 million. Some estimates have put the global total as high as 100 million.

In an attempt to devise a vaccine, medical authorities conducted tests on volunteers at a military prison on Deer Island in Boston Harbor. The prisoners were promised pardons if they survived a battery of tests. These tests were rigorous to say the least. First the subjects were injected with infected lung tissue taken from the dead and then sprayed in the eyes, nose, and mouth with infectious aerosols. If they still failed to succumb, they had their throats swabbed with discharges taken from the sick and dying. If all else failed, they were required to sit open-mouthed while a gravely ill victim was helped to cough into their faces.