How does coronavirus compare to other pandemics?

The Plague of Justinian led to the fall of the Roman Empire

Question: How does coronavirus compare to other pandemics?
Position‹6 of 6: The Plague of Justinian is the worst pandemic in history
Argument1 of 2›: The Plague of Justinian led to the fall of the Roman Empire

While not its only cause, historians argue that the Plague of Justinian hastened the fall of the Roman Empire

The argument

The Plague of Justinian was named after Justinian I, Emperor of the Byzantine Empire at the time of the first outbreak in 541 AD. The plague was named after him because a huge proportion of those killed were in the Byzantine Empire. Procopius of Caesarea blamed Justinian himself (who got the plague, but survived) for the outbreak. He believed that the plague was a punishment from God, and that Justinian was some kind of devil. This perception could have had profoundly negative effects on Justinian's future efforts to reunite the Western and Eastern Roman Empires, eventually leading to the end of the Roman Empire as a whole. Additionally, the Byzantine Empire itself was incredibly weakened by the plague, in terms of population, defense, economy and agriculture. The Byzantine Empire gradually lost territory after the plague. This also would have greatly undermined Justinian's attempts at re-unifying the Empire.

Premises

[P1]Procopius blamed Justinian for the plague and cast him as a devil, a perception that could have undermined his efforts to reunite the Western and Eastern Roman Empires. [P2] The plague severely weakened the Byzantine Empire's population, defence, economy, and agriculture, after which it gradually lost territory. [P3] These blows undermined Justinian's attempts at re-unifying the Empire, contributing to the end of the Roman Empire as a whole. [C] Therefore, the Plague of Justinian led to the fall of the Roman Empire.

Counter-arguments

The central claim conflates two different empires and misdates the fall. The Western Roman Empire had already collapsed in 476 AD — some sixty-five years before the Plague of Justinian struck in 541 — so the plague cannot have caused a fall that had already happened. The empire it did devastate was the Eastern Roman (Byzantine) Empire, which, far from falling, survived for very nearly another thousand years, until 1453. The plague undoubtedly weakened Justinian's reconquest of the West and drained Byzantine manpower and resources, but 'led to the fall of the Roman Empire as a whole' overstates a contributing blow into a cause, and the Roman East endured for centuries afterwards. There is also a gap between argument and position: even a major role in imperial decline speaks to the plague's historical significance, not to whether it was the worst pandemic — the comparison the question asks — which turns on mortality and scale, where rivals such as the Black Death and smallpox have stronger claims.

Rejecting the premises

[Rejecting P1] The Western Roman Empire fell in 476 AD, decades before the plague of 541, and the Byzantine East it struck survived until 1453, so the plague did not cause 'the fall of the Roman Empire'. [Rejecting C] A role in imperial decline speaks to historical significance, not to being the 'worst' pandemic, which the question measures by mortality and scale.