#107 – John Barry: 1918 Spanish flu pandemic—historical account, parallels to today, and lessons

KEYPOINTS

• 01

  Most of the 1918 deaths came in a 14–15-week window

  Barry, author of The Great Influenza, puts the death toll at roughly 50–100 million, the equivalent of 220–440 million people today. About two-thirds of those deaths came in roughly 14–15 weeks starting in late 1918, and influenza typically burned through any one community in six to ten weeks. In absolute numbers it's the deadliest pandemic in history, though the medieval plague killed a far larger share of the population, an estimated quarter to a third of Europe.

• 02

  Even 'swine flu' is a misnomer

  Seven of the virus's eight gene segments look avian and one mammalian, and Barry cites good evidence that humans gave it to pigs rather than the reverse. Barry has also backed away from his own theory that it began in Haskell County, Kansas, because New York's spring outbreak was hard to reconcile with that route.

• 03

  The deadly second wave was probably the same virus

  Barry calls the evidence overwhelming that the mild spring virus and the lethal autumn virus were the same, having adapted dramatically. Both waves had the same unusual age pattern, and spring exposure protected against the fall wave. Neither, however, protected against a third wave that began in February 1919. Attia likens the size of the autumn peak next to the spring one to Everest beside Kilimanjaro.

• 04

  It killed young adults, with a peak age of death of 28

  Influenza usually kills the very young and the old, but 1918 produced a 'W' curve. Barry links this to the virus binding deep in the lungs as well as the upper airway, and to strong immune responses causing what we now call ARDS. According to Metropolitan Life data he cites, over 3% of young factory workers and over 6% of young miners died, and studies of pregnant women report case-fatality rates of 21–71%.

• 05

  The war sped up the spread but didn't cause the pandemic

  With a reproductive number close to two, Barry argues, one index case catches up quickly with ten or twenty. Troopships only changed the timing. The bigger effect of the war was a government more determined to control American thinking than at any time in its history, he says, with a press that went along.

• 06

  In the West, case fatality was about 2%

  That was far higher in developing regions with populations that had never been exposed. Barry attributes the difference to Westerners' partial cross-protection from earlier flu viruses, not to better medicine. India alone lost around 20 million people, and the American Medical Association's 1927 global estimate of 21.7 million deaths was far too low because it applied Western death rates to the rest of the world.

• 07

  Telling the truth is the most important public-health tool

  Officials told the public it was 'ordinary influenza by another name' while people died within 24 hours of symptoms. When Philadelphia finally closed schools, saloons and churches, a newspaper claimed it was 'not a public health measure'. Barry argues that losing trust fuelled terror and social breakdown. In pandemic-planning groups with D.A. Henderson, nobody disagreed on transparency, and the panels agreed the spokesperson shouldn't be a politician.

• 08

  COVID death rates must compare like with like

  Recording in April 2020, Attia described Sweden's bet that the true infection fatality rate (IFR) might be close to flu's, about 0.1–0.3%, rather than case fatality rates of 1–2%. Barry stressed that flu's familiar ~0.1% is a case rate, and blood-antibody (serology) studies would push it lower still. A fair comparison needs antibody-based IFRs for both.

• 09

  2009 H1N1 was almost two different diseases

  Most people had mild flu, but in severe cases the virus also bound deep in the lung and behaved like 1918, with a similarly young average age at death. Barry adds that most of those who died had other health conditions.