How does coronavirus compare to other pandemics?

Spanish Influenza killed completely healthy people

Question: How does coronavirus compare to other pandemics?
Position‹2 of 6›: Spanish Influenza is the worst pandemic in history
Argument‹2 of 2: Spanish Influenza killed completely healthy people

While previous influenza pandemics had mostly killed only the very old or very young, the Spanish flu affected even young, previously healthy people.

The argument

While generally the flu and even pandemics more broadly affect mostly the very old and very young, Spanish flu killed people almost indiscriminately. A total of 50 million people died of Spanish flu, and about 500 million people were infected - a third of the world's population at the time. It decreased average life expectancies by, on average, 12 years. However, what was unusual about these deaths was that many 20-40-year-olds were killed, while populations of elderly people were virtually unaffected. This is extremely unusual for an influenza pandemic. It is theorised that this may be because elder people lived through the Russian flu pandemic at the end of the 19th century and were therefore immune.

Premises

[P1]Unlike typical pandemics that strike the very old and young, Spanish flu killed even healthy 20-to-40-year-olds. [P2] It infected a third of the world — 500 million people — killed 50 million, and cut average life expectancy by about 12 years. [P3] This indiscriminate lethality was extraordinary for an influenza pandemic. [C] Therefore, because it killed completely healthy people on such a scale, Spanish influenza is the worst pandemic in history.

Counter-arguments

Rivals note that 'worst pandemic' can be measured several ways, and on many of them Spanish flu is surpassed: the Black Death killed a far larger share of the world's population, smallpox killed vastly more people across its history, and the Plague of Justinian devastated the ancient Mediterranean. The unusual mortality curve that struck healthy young adults is a distinctive and terrible feature, they grant, but distinctiveness is not the same as being the worst; by deaths as a proportion of humanity, or by total lives lost over time, other pandemics have stronger claims.

Rejecting the premises

[Rejecting P3] Killing healthy young adults made Spanish flu distinctive, but distinctiveness is not the same as being the worst pandemic on any standard measure. [Rejecting C] By share of the world's population killed (the Black Death) or total deaths over time (smallpox), rival pandemics surpass Spanish flu, so its indiscriminate lethality does not settle 'worst.'