Healthy and young people not worse off from 1918 Spanish flu

A new study has found that the claim that the 1918 flu pandemic was much more likely to wipe out young, healthy adults than the old and infirm is probably wrong. Anecdotal evidence from that pandemic suggested that young healthy individuals were much more likely to be victims of the virus. Some had speculated that their fitter, youthful immune systems were their undoing. But hallmarks of health, and pre-existing disease, on the skeletons of pandemic victims have now enabled McMaster University, Canada, bio-archaeologist Amanda Wissler to lay this claim to rest…

Amanda - There are a lot of assumptions that we have about the 1918 influenza pandemic, and one of them is this idea that healthy adults were just as likely to die as unhealthy adults, or sometimes even some people say even more likely to die. Doctors were reporting that they were finding that healthy young men were even more likely to die than the unhealthy ones. So I wanted to set out, to find out if that was true, because healthy people should not die. That's not what it means to be healthy.

Chris - I know exactly what you mean because I myself have done this when commenting on past pandemics and things we've all said, and the striking thing here was this brought down even the hail and hearty, you are arguing then that this might be on shaky ground.

Amanda - I think it is. I think there's been a lot of research also particularly into the Black Death that has also tested this idea that, you know, oh my gosh, everybody was likely to die. It didn't matter who you were. But really that's not the case that they also found it in there. And so I think that's also what I expected to find with the 1918 flu.

Chris - This was more than a century ago. So how did you try and probe this?

Amanda - Most work on the 1918 flu has relied on archival records and hospital records and things like that, but there's a lot that we can't get from there. We can't look at the health of these people, especially their health over their whole lifetime. And so I look at human skeletal remains. So the skeletons are actually of people who died during and from the 1918 flu.

Chris - Are there many such specimens available?

Amanda - There aren't for good reason. You know, people belong in the ground if that's where they want to be, but no, there are probably only a handful of collections in the world that would have these individuals. And so my collection, it is relatively small, only about a hundred people who died during the time period that I was looking at.

Chris - And so what can you learn from the skeleton? How did you actually look at the remains?

Amanda - So looking at the skeleton, what happens is when a person is experiencing some stress event, and so this could be emotional stress or environmental, mal malnutrition or a long-term chronic disease stress. So what happens is your immune system and everything is trying to compensate and, and help you with that. And as a result, you get what are sort of these spongy looking markers on the bone. And so I looked specifically at the tibia, which is the shin bone, and I can see who has all of these little spongy markers on their tibia that shouldn't be there in a normal healthy person.

Chris - How did you use that to then work out whether someone was healthy or unhealthy because these people have died of the flu. So presumably that was pretty stressful.

Amanda - One of the key things here is that your bone actually takes weeks, months, or even years to change. And so these markers that I look at, this spongy looking bone would not have been caused by the flu because the flu happened fast. Like there are records of people who died within two, three days. And so instead what these spongy bone lesions show is sort of a long-term life experience of nutritional, environmental, and social stress. And so I can see the people who have these lesions we're stressed. So I compare people with certain types of lesions that look like they're more stressed versus other ones, to see which group is dying of the flu.

Chris - Got it. So basically you've got a long-term snapshot of someone's general health captured by the bone. And you can then ask, well, do I see as many people with healthy bones arguing they were healthy in life who are in graveyards because of the flu as I do? Or even more of those compared to people who clearly were unhealthy at the time they died of the flu? That would be the question.

Amanda - Mm-hmm. <affirmative>. And what's really interesting about these lesions is that I can tell based on the texture of the bone is who had an active stress when they were dying. So something that was ongoing, maybe an active disease versus someone who had the lesion, but the bone had actually healed and it was nice and smooth. So I can see in those people who with healed bone had overcome their stress, right? So in a way they were more resilient than the people who had an active stress at the time of their death. And we found that people with active stress at the time of their death had a much greater likelihood of dying in 1918 from the flu.

Chris -
So this is all a myth then, and that in fact, just as we see with COVID, preexisting health conditions are your biggest risk factor then.

Amanda - I wouldn't go so far as saying it's a myth, because there is something to it. All of our data that we looked at showed that, overall, everyone was a little bit more likely to die during the 1918 flu. Kind of like with COVID, people who normally wouldn't die were a little bit more likely to die during COVID and also during the 1918 flu. But in general, this just an easy answer of yes, healthy people were just as likely to die. Yeah. We did find that that wasn't entirely true.

Chris - How do you think this took root in the first place then? Was it just a story that improved in the telling and a juicy story was getting more traction than the more mundane, what we would expect. If you are already ill, you're more likely to be claimed by the Spanish flu pandemic. Is that what happened, do you think?

Amanda - You know, we don't fully know yet. We haven't gotten to that part of the story. But I think that part of it might be because the fact that young adults were more likely to die from the flu in 1918 compared to other years is a hundred percent true. That's not a debate. And the thing is, young adults dying is really strange. And so when you lose those people it's unexpected and it's really disruptive. And so I think it just really was just so much more memorable to everyone that people kept telling these stories and it got really incorporated into our folk memory of this event.