History of 1918 Flu Pandemic

I was watching a Nova episode about Fukushima and it seems inexplicable that the plant was designed how it was. Humans just couldn’t fathom the sort of black swan tsunami event that happened, when in hindsight we can see it was inevitable that it would happen. I’m trying to apply this sort of thinking to my own problem solving.

But the problem is that the Naysayers have been continuously right since 1918! So the problem given that we now cry wolf several times a month (a few weeks ago we were "on the verge of ww3"), is that how can you give any credibility to a real threat when it ultimately comes?

> Any given pandemic is unlikely to be on the scale of 1918.

We just need a long incubation period / low initial symptoms deadly virus and we're fucked with today's level of globalisation.

Above link is “Don’t Fear The Reaper” by Blue Oyster Cult opening to “The Stand” TV show, showing presumably dead people that contracted the super flu.

That opening scene still spooks me — a potent mix of hubris and banality.

It's right there in the article - secondary infections, especially bacterial pneumonia. This was pre-antibiotics

>Laboratory studies on the reconstructed 1918 virus began in August 2005. A report of this work, “Characterization of the Reconstructed 1918 Spanish Influenza Pandemic Virus”, was published in the October 7, 2005, issue of Science.14 To evaluate the 1918 virus’ pathogenicity (i.e., the ability of the virus to cause disease and harm a host), animal studies involving mice were conducted. The mice were infected with the 1918 virus, and measures of morbidity (i.e., weight loss, virus replication, and 50% lethal dose titers) were collected and documented. For comparison, other mice were infected with different influenza viruses that were designed via reverse genetics to have varying combinations of genes from the 1918 virus and contemporary human seasonal influenza A(H1N1) viruses. These viruses are called “recombinant viruses.”

>The fully reconstructed 1918 virus was striking in terms of its ability to quickly replicate, i.e., make copies of itself and spread infection in the lungs of infected mice. For example, four days after infection, the amount of 1918 virus found in the lung tissue of infected mice was 39,000 times higher than that produced by one of the comparison recombinant flu viruses.

https://www.cdc.gov/flu/pandemic-resources/reconstruction-19...

The referenced page goes on to detail how various parts of the 1918 virus contributed to virulence. I've seen articles that said that the reason 20-40 year old patient had more severe disease is that their immune systems were stronger, and that the lung damage is actually caused by the immune system combating the virus.

The 1918 virus started out earlier during WW I. During that time, large groups of men were being transported internationally by troop ships. While trains and ships are slower than airplanes a journey from a camp in the US to one in France probably took under two weeks.

According to "The Great Influenza" by John Barry young people died due to cytokine storms. Essentially young people have a vigorous immune system that gave an aggressive attack. 1918 flu was unique in that the deaths was not just the very young and the very old (a U shaped distribution) but rather a W shaped distribution with the middle point being 20-40 age group

Also in the book - the "spanish" flu was called that since Spain was the only place with a free press at the time (e.g., US press was not free at the time) + massing of young men in US in camps - like Ft Devens. Flu traveled from overcrowded camp to camp and then jumped to local populations along rail lines (and then overseas as troops were shipped out) He describes it well, though would make a great visual as it moves from Boston to Chicago to NYC back into Providence/Brockton (which are just south of Boston). Transmission along rail (and shipping) lines.

This paper may help give you an overview:

https://pubmed.ncbi.nlm.nih.gov/30349811-back-to-the-future-...

Aside from the other points people have made, the main hypothesis is that the 1918 flu was similar to previous pandemics which the older were exposed to when they were young, so they already had some resistance. The 20-40 year olds were unlucky in that this was their first exposure.

As others have said, the current understanding is that it was cytokine storms. Your immune system responds to an infection by creating white blood cells which in turn release cytokines to cause inflammation.

That's normally a helpful response and part of how your immune system fights infections. But it also involves raising your body temperature, breaking down cells, and changing blood pressure. When those processes go too far, they can end up hurting or killing the organism by taking out too many healthy cells or interfering with circulation.

The Spanish flu triggered a very strong immunological response. So you had a mortality spike around 20-40 years old because those were the people with such healthy immune systems that their inflammation over-reacted and killed them.

By analogy, it's sort of like your house catching on fire. Hundreds and hundreds of fire fighters pile in, so many that they building actually collapses from their weight.

It's worth mentioning that the article doesn't specify if that age group had a higher mortality % per infected, or just a higher mortality total. I'm assuming they meant the first, anyone know for sure?

It’s not clear that it did start in the US.

A while ago, I did a piece of armchair research on Spanish flu in Austria-Hungary [1]. TL;DR: the dates it occurred throughout the empire differ insignificantly. The linked blog post shows also a table with the week of highest mortality in North America, Great Britain, continental Europe, and India, copied from an old book.

[1] https://marcinciura.wordpress.com/2016/01/28/tracking-spanis...

Definitely very US focused. Misses out on some of the areas where the pandemic had the most devastating effects.

One interesting story from The Great Influenza: The Epic Story of the Deadliest Plague in History by John M. Barry:

"Freetown, Sierra Leone, was a major coaling center on the West African coast, servicing ships traveling from Europe to South Africa and the Orient. On August 15 the HMS Mantua arrived there with two hundred crew suffering from influenza. Sweating black men loaded tons of coal into her, guided by several crew. When the laborers returned to their homes, they carried more than their wages. Soon influenza spread through the force of men who coaled the ships. [...] The transport HMS Chepstow Castle, carrying troops from New Zealand to the front, coaled at Freetown on August 26 and 27; within three weeks, out of her 1,150 men, influenza struck down nine hundred of them. The death toll on her was thirty-eight. "