Step Done 2026-10-25

Tested sleepy sickness against flu in England and Wales

Collected influenza and encephalitis lethargica figures for 1916 to 1937 from 19 yearly Registrar-General reviews. No same-year link and no one-year lag. The modest US same-year link does not replicate.

How it connects

This step led us to England and Wales 1919 to 1937: sleepy sickness peaked in 1924 (5,039 cases), not after the 1918 flu

This step led us to Sleepy sickness and flu rise in the same years

This step is about What caused encephalitis lethargica, the 'sleepy sickness' of 1917 to 1928?

This step and then Compared China's 11th-century comets with Europe's

This step came after Read US death rates by cause 1910 to 1938 and tested sleepy sickness against flu