Dr. Bernard Rieux
A humanist who takes seriously his duty to help the sick, Dr. Bernard Rieux faithfully chronicles what happens in Oran as a result of the plague and thoughtfully considers the nature and effects of human suffering. As a resident of the city, he is in a good position to tell the story of what happens there, and he feels that part of his duty—apart from helping the sick—is to write an account of the plague. Although he has his own personal trial (a sick wife from whom he is parted), he consistently does his duty. In fact, he cannot think of acting any differently, even though he is not always sure why. Dr. Rieux forms friendships with Raymond Rambert, Joseph Grand, and Jean Tarrou; the interactions with these men give him opportunities to explore his understanding of suffering, love, death, humanity, and ethics.
Jean Tarrou, a visitor to Oran who is trapped there when the plague begins, enriches Dr. Rieux's account with details he records in his journal. These detailed observations are so completely objective that they do not always even distinguish between information that is important and irrelevant. Tarrou is an atheist who tries to articulate his ideas about morality, death, suffering, and duty without relying on religious language. Sometimes, he redefines religious terms, such as saint, in atheist terms. He prefers simple, direct, truthful expression. He admires those who live authentically despite the value of their actions to society, although he himself seems to feel a strong sense of responsibility to the community.
Joseph Grand is an older man who works for the city of Oran. He has had a mediocre career, without advancement. After years of a mediocre marriage, his wife has left him. Grand's main problem is that he has great difficulty finding the right words to express himself. He is trying to write a letter to his wife, to reach out to her, but he can not find the right words. He is also trying to write a novel, but he can't get past the first sentence. Part of his problem is that he is searching for the perfect words, and this search for the perfect words becomes an obstacle to any progress.
Raymond Rambert spends most of the novel trying to escape, first through legal means and then, when that goes nowhere, through illegal means. His focus is to escape and see the woman he loves; as a result, he provides a contrast to Dr. Bernard Rieux who has put his feelings for his wife to the side in order to focus on combating the plague.
Before the plague begins, Cottard lives in fear of arrest for an illegal act. In fact, when readers first learn of Cottard, he's just tried to commit suicide out of anxiety. As the plague ravages Oran, however, Cottard finds a kind of happiness. First he is comforted that now everyone is living in fear, not just him. Second, the plague provides ample opportunity for profitable illegal activities, mostly smuggling, since the gates are shut and there are no goods coming in by legal channels. When the plague recedes, Cottard, predictably, doesn't react well.
Father Paneloux first reacts to the plague by declaring in a passionate sermon that the plague is a punishment from God for the faithless ways of the citizens of Oran. However, as the plague rages on, Paneloux becomes a volunteer, taking care of the sick. He witnesses the disease attacking the old, young, rich, poor, guilty, and innocent (including the young Jacques Othon), and it becomes harder for him to believe his own words. He maintains the plague is somehow part of God's good and perfect plan, and believes that as a Christian he must accept it, or reject God. However, shortly after preaching a sermon to this effect, he becomes ill. Since his illness bears no resemblance to the plague, Dr. Rieux rules it a "doubtful case."