Despite its provocative title, this lyric never refers directly to a plague or epidemic, unless both the inevitability and the social indifference of death could be deemed "plagues" in themselves.
The litany of the title is a catalogue of the inability to escape death--the rich, the beautiful, the strong, the witty-- have no extraordinary claim to immunity. Like the poet whose refrain reads, "I am sick, I must die. / Lord, have mercy on us, " the reader is encouraged to "welcome destiny," as he mounts to Heaven, his heritage.