I think the best way for the modern reader to approach this book is with an open mind. At the beginning, I was constantly looking for clues and signs of some impending doom, and Shelley does nearly everything possible to prevent the reader from foreseeing when and how things will begin to come apart. I would recommend trusting in her ability as an author and just giving yourself over to this book. That's what I did after a few chapters, and I was pleasantly surprised by the twists and turns. Shelley focuses entirely on the human drama with little attention to the science behind the plague. She herself was the lone survivor of her group of friends and she outlived most of her children, and I think you can feel her pain and loneliness in the narrator, Verney.