Which of these two diseases was the most deadly? Seems like Spanish Flu killed a greater total number of people but there were fewer people to kill when the plague was around. Also the plague lasted many years whereas the flu mutates so quickly that it had lost it’s potency in a year or so.
I’ve read various figures for the mortality rate of untreated plague, from 60% to 99.99% (I think it depends on if it’s bubonic, septacemic or pneumonic variety you’ve lucked on) and the infection rate is variant and uncertain, but somewhere in the 50%-and-up range. Spanish Flu had a 50% infection rate and a 20% mortality rate, with mortality very health dependent (negative correlation - the fittest died in greater proportion).
I’d take my chances with the flu, thanks.
Just to determine parameters, we are comparing what is commonly known as The Black Death (Black Death - Wikipedia) from approximately 1340-1355AD to the Great Flu epidemic of 1918-1920 (Spanish flu - Wikipedia). Correct?
In terms of killing people, both seemed (statistics for the 14th century are, perhaps, less than complete) to have resulted in between 50-100 Million deaths, the flu acting much faster but plague coming back year after year.
In terms of the world, it is estimated (see reference above) that the plague killed at least 1/3 or more of Europes population and nearly 15% of the world’s population, causing drastic changes in life and society. The Flu didn’t cause nearly the upheaval that the Plague did, probably because of larger populations and more organized and national political systems (IMHO).
I for one don’t want to face either of them ever again. Yet it is not impossible. We can vaccinate against what we believe is the most likely flu virus to try and prevent it; but we can’t ‘cure’ flu. Another 1918 plague is still in the relam of possible.
Have a nice day. 
:eek:
For that matter, yersinia pestis is still alive and kicking, though possibly less virulent then the days of the black death.
It also responds to antibiotics. Flu is viral and there are fewer effective treatments.
As difficult as it may be to believe, most sources lowball the Black Death body count rather than exaggerating it. The quote one sees most often is “1/3 of Europe died,” but that really refers to the first wave of plague in 1347. Within a few years, successive waves are estimated to have killed HALF of Europe’s population.
And of course it hit Asia first, where figures are even more guesswork. Overall, the Black Death was a stupendous catastrophe to humanity.
I would speculate that germ theory and a better understanding of what was happening contributed to the difference significantly.