Shivers

A physician-scientist who develops a parasitic agent intended to restore primal human impulses. He theorizes that modern people are over-intellectual and aims to unleash unchecked sexuality to reawaken humanity. His experiments trigger the outbreak and he ultimately takes his own life.

A resident plagued by stomach convulsions who becomes a host for the parasite. He is emotionally volatile, tries to coerce his wife into sex, and embodies the film’s theme of eruption of primal instincts. His actions catalyze the spread of infection.

A resident doctor who discovers the bodies and leads attempts to understand and contain the outbreak. He remains rational and determined but is overwhelmed by the parasite’s spread and becomes infected at the climax.

Hobbes' medical partner who warns of the parasite’s dangers. He is killed by Nick after being infected and becomes a cautionary figure about scientific ambition and its consequences.

Nurse and lover of Roger who becomes infected and experiences a dreamlike blend of eroticism and death. She fights to escape the building but ultimately succumbs to the outbreak.

Nick’s wife who becomes infected after encounters with parasites passing between residents. She represents the intimate spread of contagion and the breakdown of trust in relationships.

Janine’s friend who is infected and seduces Janine, acting as a focal point for the contagion chain within the apartment complex.