Contagion

The film follows several interacting plotlines, with no single protagonist, over the course of several weeks from the initial outbreak and attempts to contain it, to panic and decay of social order, and, finally, to the introduction of a vaccine.

Beth Emhoff (Gwyneth Paltrow) returns from a business trip to Hong Kong, after briefly stopping in Chicago to cheat on her husband with an old flame. Two days later, she collapses with severe seizures in her suburban Minneapolis home. Her husband, Mitch Emhoff (Matt Damon), rushes her to the hospital, but she dies from an unknown disease. Mitch returns home and finds that his stepson, Clark, has also died from similar symptoms. Mitch is put in isolation but turns out to be immune to the disease. He and his daughter attempt to flee the city, but a quarantine has been imposed, and they are forced to return to their home to face a decaying social order and rampant looting of stores and homes. Mitch struggles to give his daughter, who has a lengthy wait for a vaccination and is thus quarantined to their house, a sense of normality while trying to come to terms with his own loss. For prom night, he decorates the living room and invites his daughter's boyfriend, who got vaccinated in the meantime.

In Atlanta, representatives from the Department of Homeland Security meet with Dr. Ellis Cheever (Laurence Fishburne) of the Centers for Disease Control and Prevention and express fears that the disease is a bioweapon intended to cause terror over the Thanksgiving weekend. Cheever sends Dr. Erin Mears (Kate Winslet), an Epidemic Intelligence Service officer, to Minneapolis to begin the investigation and traceback. Dr. Mears has to negotiate with local bureaucrats reluctant to commit resources and becomes infected with the disease while staying at her hotel. The Minnesota National Guard arrives to quarantine the city, and a badly deteriorating Dr. Mears is moved to the field medical station she helped set up, where she later dies.

Investigations into cures via treatment protocols or vaccines initially prove fruitless as scientists cannot find a cell line to culture the MEV-1 virus. Professor Ian Sussman (Elliott Gould) violates orders from CDC scientist Dr. Ally Hextall (Jennifer Ehle) to destroy his samples and identifies a line of bat cells that will support research of a vaccine. At the CDC, Dr. Hextall uses this breakthrough to begin to characterize the properties of the virus, which turns out to have a mix of genetic material from bat and pig viruses and appears to spread via fomites with a basic reproduction number of two.

A conspiratorially-minded freelance journalist named Alan Krumwiede (Jude Law) posts video blogs, claiming that he has recovered from his sickness using a homeopathic cure based on forsythia. Panicked people attempting to obtain forsythia overwhelm pharmacies and also accelerate the contagion as infected and healthy people congregate. Krumwiede leaps to national attention and, during a television interview, accuses Dr. Cheever of informing friends and family to leave Chicago before a quarantine is imposed. It is later revealed Krumwiede was never sick but was attempting to boost demand on behalf of investors in the companies producing and distributing the treatment.

Dr. Hextall identifies a potential vaccine, using an attenuated (live) virus. Because of the difficulties of human subjects testing, she follows the precedent of other vaccine researchers and inoculates herself first. Hextall visits her gravely-ill father in the hospital to expose herself to the virus and test the vaccine. Production of the vaccine is rapidly ramped up, and the CDC awards vaccinations via a random lottery based on birth dates for one full year until every survivor is vaccinated. Dr. Cheever, remorseful about the deaths that his delayed action indirectly caused, gave his fast-tracked vaccination to the son of a janitor (John Hawkes) he works with at the disease center.

Dr. Leonora Orantes (Marion Cotillard) is a World Health Organization epidemiologist who traveled to Hong Kong to find out where the sickness originated. While there, she identifies Emhoff as patient zero. Epidemiologist Sun Feng (Chin Han) kidnapps Orantes to use her as leverage to obtain the first vaccines for his village. After the vaccines arrive, Feng exchanges Orantes for the vaccines, which turn out to be placebos. Orantes rushes to notify the villagers.

The film concludes by showing how the virus originated. Emhoff's Minneapolis-based mining corporation is actively clearing jungle, and a bulldozer knocks over a palm tree in which bats were nesting. They fly out, and one bat, the vector, lands on a banana plant, eating a chunk of banana. Not having its tree to return to, the bat flies to a nearby hog building, where it drops the banana into a pig sty, where a pig eats it. The pig is then sold and slaughtered and is shown being prepared by a chef in the Macau casino Beth Emhoff was in. The chef smears the pig's blood on his apron but does not wash his hands before shaking Beth's hand, thereby infecting her with the disease.