In 2002, Hollywood released the first Resident Evil adaptation of the wildly popular video game, setting off a film and TV franchise that is still continuing twenty years later. But there’s one aspect of its legacy that's worth taking a closer look at today: the movie’s fictional T-virus.
A futuristic entity known as the Umbrella Corporation manufactures a viral bioweapon in their laboratory. Soon, the virus escapes through the facility’s air ducts and causes a massive disease outbreak that turns people into cannibalistic zombies. The protagonist and the rest of her crew fight off the zombies to prevent the spread of the disease to the outside world.
To be clear: The virus isn’t real (nor are zombies), but is it even plausible? (Spoilers ahead for Resident Evil (2002).)
Reel Science is an Inverse series that reveals the real (and fake) science behind your favorite movies and TV.
Are zombie viruses real?
If you haven’t watched the movie in a while, here’s a quick recap of what the virus does: It turns people into mindless, bloodthirsty zombies with only basic motor functions, little intelligence, and no working memory. According to the movie, these human zombies “are driven by the basest impulses, the most basic of needs: The need to feed.”
William Schaffner, a professor of infectious diseases at Vanderbilt University, tells Inverse: “there is no such virus that will do that.”
However, some real-life viruses resemble certain aspects of zombie-ification, if you will. Some infectious diseases cause inflammation of the brain and affect our thinking and behavior — a condition known as encephalitis.
“You could have brain tumors growing, that make you do unusual things — alter your personality. Make your reasoning not very effective, and even in induce seizures,” Schaffner says.
Some scientists have likened Rabies — which humans can catch when an infected animal bites or scratches a human — to a zombie-like virus due to its ability to cause rage and confusion, but again, that’s because Rabies causes encephalitis.
The trailer for Resident Evil (2002).
“I couldn't think of a virus that reduced you to very primitive functions, such as seeking food,” Schaffner says.
Donald J. Alcendor, an adjunct associate professor of pathology, microbiology, and immunology at Vanderbilt University School of Medicine, tells Inverse there is a little-discussed virus that shares some features with typical zombie viruses.
That virus is the John Cunningham virus (JC for short). It’s a type of polyomavirus, which is a DNA virus family that exists in mammals and birds. A majority of human adults have been exposed to the JC virus and don’t even know it.
“If your immune system is intact, this is a virus you will carry throughout your lifetime. And it shouldn't cause you a problem,” Alcendor says.
The reason most of us have never heard of the JC virus is that the immune systems of healthy adults can typically fight it off. But immunosuppressed adults cannot fight off the virus as easily. In their bodies, the JC virus progresses from a dormant to an active state and starts replicating, causing progressive multifocal leukoencephalopathy (PML).
“I couldn’t think of a virus that reduced you to very primitive functions”
This condition destroys the myelin, which forms a protective layer around your brain’s neurons. The individual may display some characteristics that we typically associate with zombies, including personality changes, clumsiness and stumbling, paralysis, and grunting due to speech communication challenges.
“If you think about something that would give you zombie-like pathologies, I would say the closest thing in my mind would be infection with the JC virus,” Alcendor says.
It’s important to emphasize that people with the JC virus are not going around attacking people like zombies; most are bedbound. Yet it’s still a dangerous virus for those it infects since there’s no real treatment.
“I would say 50 percent of people that are diagnosed with PML are dead within three to six months after diagnosis,” Alcendor adds.
Is the T-virus realistic?
Here’s a description of the virus from the movie, which explains how it reanimates the body upon infection:
Even in death, hair and fingernails continue to grow. New cells are produced and the brain itself holds a small electrical charge...the T-virus provides a massive jolt both to cellular growth and to those trace electrical impulses. Put quite simply: it reanimates the body.
To put it simply: Real-life viruses cannot bring the dead back to life.
“We don't know if anybody who's been infected with a virus who's been restored to life in some form,” Schaffner says.
The T-virus’ mechanism of boosting cellular growth — causing infected people to mutate into an even scarier being upon feeding human flesh or “fresh DNA” as the movie puts it — is also highly unrealistic.
Viruses “don't encourage the growth of cells,” says Schaffner, adding that they “usually destroy them.”
The T-virus and Covid-19
SARS-CoV-2 — the virus that causes Covid-19 — cannot turn people into zombies. But there are some similarities between T-virus and SARS-CoV-2 that you might not have considered.
“COVID is not likely to make you zombie-like, but what it can do is that it can put you in a cage in a state of acute respiratory distress,” Alcendor says.
Perhaps the most interesting comparison we can make between the two viruses is the way they spread. The T-virus can change from liquid transmission to airborne to blood-based, depending on its environment, making it highly contagious.
While Covid-19 is primarily an airborne disease, surface transmission is still possible, though extremely unlikely. Exposure to respiratory fluids also spread the disease. To be clear: Covid-19 isn’t a blood-borne disease, but it can replicate in blood cells.
So it’s not at all uncommon for viruses to spread through multiple transmission pathways, though a better comparison to T-virus might be norovirus, which Schaffner says is a “highly infectious” virus that can be transmitted through a number of ways involving personal contact.
But it’s less likely for a real virus’ transmission pathway to mutate depending on the environment — unlike the T-virus. The Covid-19 virus mutated to become more contagious, but it didn’t change the way it infected people. But other viruses have changed transmission modes. Zika virus’ mode of transmission — which doctors previously thought spread only through mosquitoes — mutated so that it could also infect through sexual contact.
“We had never heard of a mosquito-borne virus that could also be transmitted through sexual intimacies,” Schaffner explains.
But it would be unlikely for an airborne SARS-CoV-2 to mutate to change its transmission pathways as easily as the T-virus does, providing us some peace of mind in this pandemic.
“ I couldn't think of a virus that could readily mutate so that it has a radically different mode of transmission,” Schaffner says.
Resident Evil (2002) is streaming now on Netflix.