How does coronavirus compare to other pandemics?

The Plague of Justinian killed the highest proportion of people

Question: How does coronavirus compare to other pandemics?
Position‹6 of 6: The Plague of Justinian is the worst pandemic in history
Argument‹2 of 2: The Plague of Justinian killed the highest proportion of people

The Plague of Justinian is thought to have killed around half of the population of the entire planet.

The argument

Supporters of this position hold that the worst pandemic in history should be judged by the share of humanity it removed rather than by an absolute body count, and that on that measure the Plague of Justinian has no rival. The outbreak is dated to 541 AD and is thought to have spread from rats. On the account proponents give, it probably began in Egypt, was carried across the sea to the Mediterranean countries, and then devastated Constantinople, the capital of the Byzantine Empire. From there it infected and killed people across Europe, Arabia, North Africa and Asia. That reach matters to the argument: an outbreak confined to a single region could not plausibly claim the highest proportion of the world's population, whereas one spreading across this much of the inhabited world can. Proponents accept that the toll itself is debated by historians. The estimate they work from is that between the original outbreak in 541 and the recurrences over the following two centuries, between 30 and 100 million people died. The weight of that figure lies in the denominator. Measured against the much smaller world population of the time, a toll of this size could represent roughly half of everyone then alive, a proportion that supporters argue no later pandemic approaches however much larger its raw numbers appear. The claim is therefore comparative rather than absolute. On this view, later pandemics may have killed more individuals simply because there were more individuals to kill, while the Plague of Justinian killed a far greater fraction of those living. If the worst pandemic in history is the one that destroyed the largest part of the human population as it then stood, the argument runs, the title belongs to the Plague of Justinian, whose global mortality rate on these estimates was the highest of any recorded outbreak.

Premises

[P1]The Plague of Justinian, beginning in 541 AD, spread from Egypt across the Mediterranean, Europe, Arabia, North Africa, and Asia. [P2] Between the original outbreak and reoccurrences over the following two centuries, an estimated 30 to 100 million people died. [P3] That toll could represent roughly half the world's population at the time, the highest global mortality rate of any pandemic. [C] Therefore, the Plague of Justinian killed the highest proportion of people.

Counter-arguments

Although many claim that the Plague of Justinian killed half of the world's population, this is not backed up. Other estimates suggest that roughly 25 million people were killed, a figure closer to 10% of the world's population.

Rejecting the premises

[Rejecting P1] The Plague of Justinian did not kill half of the world's population.