Mythbusting thriller science: World War Z

Brad Pitt’s zombie apocalypse SciFi action thriller movie was just released for home viewing and I saw it. I’m not going to review World War Z but I have to make a few comments about zombie science, especially microbiology.

WWZ is formulaic so the minor reveals below shouldn’t affect your enjoyment of the movie, but I have to warn: SPOILER ALERT.

Maybe if I were more familiar with the zombie genre, I would have been less surprised to discover that World War Z is a pandemic movie. I was particularly struck by numerous parallels with Contagion (Matt Damon, Gwyneth Paltrow), the most scientifically accurate pandemic / plague / killer virus movie ever made.

Which is bizarre, because the microbiology of WWZ is silly.

And yet…the epidemiology is right.

You’ve got an emerging (new) virus. Maybe it jumped species into humans. New viruses like that tend to be hot–lethal with a high mortality rate, fast spreading because the population has no immunity. The zombie virus certainly is hot.

You’ve got a clear pathway of transmission: bites. No wonder the people in the movie talk about rabies.

You’ve got all the social consequences of a massive pandemic: fear, riots, looting, collapse of authority.

Unlike in Contagion, you also have aggressive, fast-moving undead zombies. Zombies certainly are efficient disease vectors but I’m not sure they’re scarier than the guy who can’t stop coughing on a bus in Contagion.

Speaking of fast…I shouldn’t have to point out that the time scale of infection and undead conversion is a bit accelerated. Brad Pitt’s character counts ten seconds from bite to new zombie. In ten seconds, I don’t think your blood even makes a full sweep through the body.

All disease-causing (pathogenic) viruses have an incubation period. This is the time between exposure and first signs of sickness. Incubation periods can be measured in years (HIV), months (rabies), weeks (polio), or days (influenza & the common cold). They are not measured in seconds.

Interestingly, the movie implies that the zombie virus is evolving. The first cases in Korea had a longer incubation period–which would be necessary if the zombie plague were spreading by air travel, as is stated as an explanation for why the plague strikes multiple continents at once.

On Korea: Pitt’s character escorts a virologist to a location in Korea where the first (“index”) case of zombie may have occurred. That’s fine. Finding a virus’ source can be crucial for understanding the epidemiology of how the virus spreads, how people are exposed to it, and how the virus might be controlled.

However, the stated reason for the virologist to go to the location of the index case is to develop a vaccine. (At this point in the movie I annoyed my children by whispering to them about how vaccines are really made.)

Vaccines are made from the virus you’re vaccinating against. Vaccines can be made from pieces of the virus (for example, hepatitis B vaccines), from dead virus (injectable Salk polio vaccine, flu shot), or from “attenuated” virus which isn’t dead but has been rendered harmless (MMR vaccine).

To make any of these, you need the virus. You do not need anything from or about the original source of the contagion. In WWZ, there is no reason for the virologist to travel to Korea. He just needs some blood from a zombie–and a really, really good Biosafety Level 4 containment facility.

{To make a vaccine against a virus, you typically need a cell culture line or chicken embryos inside fertilized eggs to produce virus. Hmmm. I’m picturing zombie chick embryos egg-tooth attacking their way out of a shell and into human flesh. Or zombie cell cultures piling up to climb the wall of their dish…}

Speaking of BSL4 facilities, they obviously needed one at the WHO research facility. And better staff: The scientist who zombied-out while analyzing zombie blood clearly wasn’t following basic biosafety protocols.

My final thoughts are on the use of a lethal bacterial infection to make people “invisible” to the zombies. Kind of clever plot idea, even if silly. Zombie or not, there is no technology to instantly recognize the presence of infection in an otherwise healthy-appearing human at a distance.

More importantly, mainlining typhoid or typhus or whatever undefined bacterial pathogen they use in the movie might protect you from zombie bites but it still gives you a whopping case of typhoid or typhus or whatever. You’re not going to be in much condition to go out and battle zombies. Although if the incubation period is long enough, I suppose you might have a day or two. (The risk of antibiotic failure would rise the longer you waited to begin treatment.)

That’s all the zombie plague microbiology I have. I’ll leave you with some images that fit equally well in either of the pandemic movies. Social breakdown and fear of infection are the same, whether the story is about a realistic flu or a crazy zombie agent.


Which movie?


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2 Responses to Mythbusting thriller science: World War Z

  1. Pingback: New release book review: REEL BIOHORROR by Victoria Sutton |

  2. Morgan says:

    Thanks for this review. In pretty much confirms my decision not to pay theater prices for this. As you pointed out, Gweneth’s cough before munching nuts in the airport bar was more frightening than so much explicit imagery in lesser films.