The group hardest hit in 1918 was people between 20-40 years old. People between 29 and 40 clearly fall in that category.
They do but those 1918 age 20-29 would not have suffered the 1889 outbreak and as such would not have antibodies which would not add to cytokine stroms. This would of course be the case for the 29-40 years old.
Not sure I am understanding your argument here. People who are malnourished are generally more susceptible to disease, not less.
Just my arguement - you were argueing that those well nourished in their prime were those hardest hit because of cytokine stroms; but in Europe peoples were suffering from rationing and malnourishment if not famine; hardly then the group to suffer from cytokine stroms.
But those hit it seems were generally male in the fighting age so of course they should be hit badly, as they were. Antibodies and cytokine stroms or not.
I'm just lacking figures for areas like Central Europe; the German army wasn't as well fed as the Allies.
On the other hand malnourishment could be the end of the scale - BOTH contributing to the mortality rate. But if malnourishment is as bad as good health which is serving to cytokine stroms both making for increased mortality then other age groups would be just as badly affected in Europe - but numbers are lacking.
The quote in your source referring to people who contracted the Russian flu of 1889 being in their 40s to 80s is referring to the people who died. The virus infected people of all age groups...and created antibodies in them. The young children of 1889 were part of the 20-40 year old group which died in droves in 1918.
No it says:
In 1889, the Russian flu pandemic struck those who, by 1918, were in their 40's to 80's.
Counting back 29 years the affected group in 1889 would have been 11-51 years of age.
Those would be 40-80 in 1918 and thus not in the range of those with the highest mortality rate.
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It seems like - from what I've been able to glimpse (and as noted I lack some figures from Europe) that
a. antibodies
could have an innoculating effect on the older victims.
b. cytokine stroms
could have an increasing effect on the mortality rate within the most affected groups in 1889 and 1918.
c. you cannot treat the World according to US statistics!