Which nation released the first pandemic virus? Why? In the end, rationale doesn't really matter, only consequences, and in the brutally dystopian American society of this novel, consequences are enormous.
The already ill, and all those who test positive are herded into internment camps where, in the interests of science, they are subjected to experiments as were concentration camp inmates in World War II, experiments designed to dehumanize and destroy them.
There is escape, through death; and rarely, escape out of the camp. But escape to what? The vast wasteland of isolation, storms and ice melt- caused sea level rise, and few people, but always the struggle to survive. Kill first or risk dying, no compassion or empathy, just a bleak and empty terrain. The narrator mourns the loss of "vibrancy" of the world-that-was, and concludes: "Everything is dulled or dampened or lessened or vacuous." That is my conclusion, too: this is not a brave New world, not a world offering any incentive for survival.