How serious was this fictional plague?

The narrative takes set in 2073, sixty years after the earth was depopulated by an uncontrollable pandemic known as the Red Death. James Smith is one of the living survivors before the scarlet plague struck the San Francisco area. (London, J, 1912)

The Scarlet Plague caused people to turn red, especially on their faces, and to lose feeling in their lower extremities. Victims died on average within 30 minutes of initially experiencing symptoms. Despite the public's faith in doctors and scientists, no cure has been discovered, and many who attempted to do so have died as well. This illness was depicted as extremely serious, and no one who ever got it survived. This is what drew me to the narrative in the first place: how the plague's severity can be linked to the pandemic we've grown accustomed to. (London, J, 1912)

London took his inspiration from an 1842 short story written by Edgar Allen Poe. Both Poe's and London's stories are part of an apocalyptic fiction genre in which humanity is virtually wiped out by a worldwide plague. (Riva, M. A., Benedetti, M., & Cesana, G. 2014)