Throughout the course of the book, observations that Lena makes and stories that she shares of other citizens who have been ravaged by the disease make a pretty good case for eradicating it, much like polio or whooping cough have been eradicated, which also means, not entirely gone. When she thinks about love and the vulnerability that it requires she remembers that "Everyone you trust, everyone you think you can count on, will eventually disappoint you. When left to their own devices, people lie, keep secrets and change and disappear." Although she is not yet eighteen, Lena has some experience with this. Her father died when she was young and her mother was left to raise her and her sister Rachel, who is nine years older. When Lena was six her mother committed suicide. A passionate woman, Lena's mother was seemingly incurable. She had gone under the knife three times, the last time without anesthesia, and she still wore a memento of her husband's on a chain under her clothes. Lena has memories of her mother shutting the blinds and stuffing the cracks in the doors so that she and her daughters could listen to music and have dance parties. She remembers her mother showing her tenderness when she fell and hurt herself, only to stop when another mother noticed and expressed her disapproval. Yet, Lena also has memories of her mother crying through the night, alone in her bed. As Lena realizes after experiencing it, love is "the deadliest of all deadly things: It kills you both when you have it, and when you do not. Love: It will kill you and save you, both."
Also, Delirium, as well as Oliver's first book, Before I Fall, which I have been dying to read since it came out, have both been optioned and are being made into movies!