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Comment by saalweachter | Hacker News Reader

Fun fact: while the IFR of the seasonal flu is around 0.1%, there's around a 2.5% chance you will die from it.

The thing about endemic diseases is that we get them over and over and over. Eventually it gets you.

I was really hopeful at the beginning of the COVID-19 pandemic that we would start taking the flu more seriously. There was essentially no flu season that year because of the precautions taken for COVID; we are actually removing one of the strains from flu vaccines next year because it went extinct.

Things have changed since 2019. In 2023, only around 1.5% of deaths were from the flu; of course, another 1.5% of deaths were from COVID. So as things stand now, instead of a 2.5% chance that we will eventually be killed by our major endemic respiratory disease, there's a 3% chance we will eventually be killed by one of our two major endemic respiratory diseases.

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> The thing about endemic diseases is that we get them over and over and over. Eventually it gets you.

The bigger thing is that the IFR differs dramatically based on age, and eventually you either die from something else or get old.

If it weren't for the IFR going up with age, you'd still have a very low lifetime chance of dying from the flu.

Yes and no; younger people also die less.

The flu death rate in the 0-4 age bracket for the 2022-2023 was 1.2 per 100k, compared to 26.6 per 100k for the 65+ age bracket. Meanwhile, the death rate of the 1-4 age bracket [different sources; different buckets] was only 28 per 100k, compared to 2000 per 100k for ages 65-74 or 15,000 per 100k for ages 85+.

So, flu deaths are a larger percentage of child deaths than than elder deaths, even though most people who die of the flu are old. The answer to "How can we most readily lower child mortality?" is always going to be "Keep infectious diseases under control."

The largest portion BY FAR of everyone's lives (beside infant fatalities) is the portion between 4 and 65.

>Fun fact: while the IFR of the seasonal flu is around 0.1%, there's around a 2.5% chance you will die from it.

That's an incorrect statement unless the age distribution of people on this forum exactly matches the age distribution of the US population, which it doesn't. The overwhelming majority of flu deaths are concentrated in the elderly; someone under sixty is orders of magnitude less likely to die than someone older than eighty.

I don't think this has to be incorrect. Or that your "unless the age distribution...." needs to be true either.

Everyone eventually dies. When that happens, as things currently stand, it will be a 2.5% chance the cause will be the flu.

You might die young or old. Across those possibilities, it is 2.5%

That can be consistent with the idea that if you were to die next year, it probably (i.e., much less than 2.5%) won't be the flu because you are a young person.

There is no way the fatality rate of someone with my health profile or the health profile of the average HN user has a 2.5% chance to die from the flu this year. That must be including sick and/or elderly.

Most people don't die every year; 2.5% [well, 1.5% last year] of the people who die, die of the flu.

2.5% of deaths caused by flu is not the same as a 2.5% chance of dying of the flu, though.

Unless you do something unusual, that's almost exactly what it means. (Almost exactly because new causes appear, and those chances won't stay constant during your life.)

No.

US population: 330M

Deaths per year (approx): 3.46M (call it 1% of the population)

2.5% of deaths: 86,500 people

Number of flu infections, per year: 9M .. 41M

2.5% chance of dying of flu: 225,000 .. 1,025,000 people

Number of deaths due to flu, per year: 4,900 .. 51,000

Actual chance of dying of flu (2010-2022): 0.01% - 0.5% [0]

[0] min ((4900/41000000), 4900/9000000)) .. max (51000/41000000, 51000/9000000)

The OP didn't say "per year". You added that one gratuitously.

It makes no difference at all. But whatever set of statistics you use has to represent the same period. We could use daily deaths from flu, or decadal deaths from flu, or forthnightly deaths from flu .. as long as the total deaths we're comparing with cover the same period.

Thanks for this breakdown, I was too tired to protest but I completely agree with your interdiction.

I mean, I began by saying:

> the IFR of the seasonal flu is around 0.1%

We're all going to die some day. Based on current causes of death, there's a 20% chance, give or take, that it will be heart disease. A 20% chance it will be cancer. A 2% chance one of us will die from kidney failure. And around a 1.5% chance it will be from the seasonal flu, which has an IFR of 0.1% or less.

Anyway, bringing this back around to the Spanish flu, it's fascinating, to me, that if you were alive in 1918, there was around a 1% chance you would die, that year, of the Spanish flu, and around a 2% chance you would die, years or decades later, of a seasonal flu. Pandemics get you upfront, all at once, epidemics get us eventually, over time.

"x% chance dying of the flu" has two vastly different meanings.

"If you die, then the cause of death is to 2.5% the flu" is one meaning. Likely close to correct.

"With 2.5% you will die this year a death caused by the flu" is another. Unlikely to be correct.

Thanks, apologies for the misunderstanding. I wonder what the number is for pneumonia.

This doesn't seem correct. Deaths per year are around 3.5M; deaths from flu vary between 5k and 50k.

TBH I'm not sure where I'm getting the 2.5% number from; it's the one that stuck in my memory from the last time I dug into this data. It's entirely possible that my memory is wrong or the data I was looking at represented an outlier in flu deaths.

For the 2023 / 1.5%, I referred to the provisional vital statistics for 2023: https://wonder.cdc.gov/controller/datarequest/D176;jsessioni...

Looking at past years (https://www.cdc.gov/nchs/data/databriefs/db355_tables-508.pd...), I get more like 2%, even for bad flu years like 2018. So that 2.5% number is probably either completely misremembered or based on provisional data that has since been revised downward.

Yeah, 1 - 1.5% seems inline with most data. That is: about 1.5% of all deaths are deaths from flu.

However, deaths among those infected by flu are much, much smaller than this (because the number infected is much, much bigger than the total number of deaths)

> Most people don't die every year

I don't think anyone dies every year. Just once. /s

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