An innocent cough launches a deadly pandemic in Contagion, the new thriller directed by Steven Soderbergh. Critics and scientists alike have touted the movie as a more realistic depiction of disease transmission—no movie stars turn into flesh-eating zombies, and the previously unknown disease does not kill every person it encounters. But despite some impressively realistic details, there are still parts of the movie that would be pretty unlikely in real life, several scientists say.
SPOILER ALERT: KEY PLOT POINTS DIVULGED AHEAD
In the movie, Gwyneth Paltrow’s character, a Minnesota executive named Beth Emhoff, falls ill with a cough on a company trip to Hong Kong. She infects several other unfortunate people on two continents. Soon, places as remote as Durbin South Africa and San Francisco are overrun with the disease, a Paramyxovirus dubbed MEV-1, which contains bat and pig DNA.
Along the way, widespread chaos ensues, several A-list actors have chances to be both tragic and heroic, and the world is saved in the end by intrepid scientists who whip up a vaccine in less than six months.
Yet the least plausible part of the scenario is the very beginning, said Bill Hanage, an epidemiologist at Harvard University. “I’m not entirely sure why it would be Gwyneth Paltrow who would be so important other than the fact that she’s a movie star,” he says. “In reality, something that would have been that infectious, you would expect there to be rumblings in local populations.” A factory worker at the pig farm, for instance, would be a more likely patient zero than a jet-setting Western business executive.
MEV-1 is based on a real pathogen, called Nipah virus, which causes respiratory symptoms, encephalitis, seizures, and kills 45 to 90 percent of its victims. Nipah has a reservoir in bats and has sickened hundreds of people in Malaysia and Bangaldesh. But it usually doesn’t transmit between humans very well, says Pramila Walpita, a virologist at the University of Texas Medical Branch at Galveston, who is developing a vaccine for Nipah.
In comparison to Nipah virus, MEV-1 is rather restrained, killing only one out of every four of the people it infects and spreading to two people for every one who gets the disease, a very realistic transmission profile, Hanage says.
At the end of Contagion, viewers see a flashback that explains where the fictional MEV-1 came from. A native bats’ habitat is razed to build a factory, and a bat flies into a pig farm, where a fruit dropped from its mouth mingles with food eaten by the pigs. One of the slaughtered pigs is prepared in a swanky Hong Kong restaurant where Emhoff shakes hands with the chef—who presumably has some of the new virus on his hands—and Voila! Global pandemic.
That pathway from animals to humans is very realistic, says Barbara Reynolds, a crisis communications specialist at the Centers for Disease Control in Atlanta. Close interactions between humans and animals have caused pandemics, like the morphing of a bird flu into the 1918 Spanish influenza.
“We know about 75 percent of the threats we face come from animals and insects. The idea that as we interact with our natural environment there’s a potential for a virus to mutate and be transmitted to humans is very plausible,” Reynolds notes.
But the fact that it spread from the chef to Emhoff with no prior history of infecting anyone else, ever, is unlikely, Hanage agrees. “That suggests a very rapid process of suddenly becoming fully transmissible in human.” In reality, the disease would mostly live in animals and be transmitted from animals to humans for a while, gradually becoming more easily transmitted from human to human, he says.
Walpita thinks that such a dramatic transmission may not be realistic “at this minute,” but that a similar level of infection could one day emerge in Nipah or other paramyxoviruses, because they are RNA viruses, which don’t employ the same genetic proofreading used by DNA viruses. As a result, they mutate very quickly and can become much more infectious; the annual outbreaks of Nipah in Bangladesh are often different strains, she said.
While the virus in Contagion is completely unknown on day zero, intrepid scientists culture it in just 12 days, and a vaccine is ready about 4 months later. That’s a stretch, Walpita says.
“People have been working on Ebola vaccine for how long?” she continues. “But there is still no vaccine.” Respiratory syncytial virus—which is a paramyxovirus just like Nipah and the fictional MEV-1—has been studied for more than 40 years, yet scientists still haven’t found a vaccine.
The only way a vaccine could be on the shelves in a few months is if researchers had anticipated future outbreaks by creating vaccine candidates in advance that had already gone through several safety and efficacy trials, she says.
“The best solution to these things is to be vaccine prepared,” she adds, so that if there was such a catastrophic outbreak, “at least we are prepared to make a vaccine on a fast track.”
Watch a trailer for the movie: