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