One reason Steven Soderbergh's new thriller 'Contagion' seems so scary is that its depiction of a worldwide viral pandemic seems all too plausible. That's no accident; Soderbergh and screenwriter Scott Burns made a point of consulting with actual scientists to make sure their movie stuck close to a realistic scenario. Of course, consulting with scientists takes filmmakers only so far down the path of realism. Even in 'Contagion,' there is some dramatic license taken, some science that is fudged for dramatic purposes. (That's the case with all bio-horror thrillers whose big bad monsters are microscopic viruses.) We looked at several viral scarefests to see how they stack up scientifically. The results may surprise you.

Movie: 'Contagion'
Scenario: A new virus spread by inhalation kills its victims within hours and spawns a worldwide pandemic. Public health workers try to curtail the social chaos while working on a vaccine.
How Scientifically Plausible Is It? Much of the movie was vetted by Dr. Ian Lipkin, the director of the Center for Infection and Immunity at Columbia and co-chair of the National Biosurveillance Advisory Subcommittee. He worked with Burns from day one and was also on set to coach the actors on scientific niceties like lab behavior or what a seizure looks like. The virus is modeled after SARS, the 2003 respiratory virus that caused a worldwide panic but fizzled out after causing only about 900 deaths around the globe. Unlike SARS, the 'Contagion' virus attacks the central nervous system as well, causing what Lipkin admits are more cinematic symptoms. Talking to Salon, Lipkin also acknowledges that the vaccine is developed faster than it would be in real life, but otherwise, he says, the movie is not only plausible, but "also something in the way of a wake-up call."

Movie: 'Outbreak'
Scenario: An airborne virus that kills its victims within 24 hours decimates a small California town. The military authorities quarantining the town threaten to wipe it off the map before the disease can spread into a nationwide pandemic, but a quick-thinking scientist (Dustin Hoffman) manages to find the monkey that initially spread the virus, and he develops a vaccine from antibodies in her blood.
How Scientifically Plausible Is It? Like 'Contagion,' 'Outbreak' had a team of prestigious scientific advisers, including AIDS vaccine researcher Donald Francis. It's not clear how much the filmmakers paid attention, however. The virus is based on Ebola, but that notorious African virus has killed only about 1,500 people worldwide since it was discovered 35 years ago. In the movie, the virus causes ugly skin lesions, though when female lead Rene Russo gets infected, she gets only a flushed, rosy glow. Francis has said that Method actor Hoffman spent a lot of time with him and studied him intensely, but only to get his mannerisms and clothing choices right, not for scientific accuracy. Scientists did, however, teach the actors how to pronounce medical terms like "gamma globulin" and "aerosolized." Scientist Donna Cline, another consultant on the movie, convinced the filmmakers to portray the virus as stationary when seen through a microscope, rather than writhing menacingly, as they had wanted. Once Hoffman has the antibodies, he develops the vaccine in a matter of hours, rather than months.

Movie: '28 Days Later'
Scenario: A laboratory virus dubbed "Rage" is spread to humans via a bite from an infected chimp. The virus, whose symptoms become apparent in seconds, turn victims into psychotics and virtual zombies. After much of Britain is infected, a handful of survivors try to flee to safety.
How Scientifically Plausible Is It? Not especially, you would think. But an article at Cracked, of all places, notes the similarity of the "Rage" virus to mad cow disease, which manifests itself in humans who've eaten tainted meat as Creutzfeldt-Jakob disease. C-J can make people stumble and twitch like zombies and hallucinate. Which suggests that we're all just one bad hamburger and a little bit of excess serotonin away from becoming "Rage" zombies. Uh oh.

Follow Gary Susman on Twitter @garysusman.