Learning From World Of Warcraft’s Virtual Pandemic

12:12 minutes

a video game depicting various fantastical characters fighting a large, demonic serpent character in a ruin setting
Credit: Blizzard Entertainment

The widespread infection of roughly four million virtual characters all started with a giant snake demon. In 2005, the massively multiplayer online video game World Of Warcraft introduced a special event raid, where groups of players could team up to fight a giant snake demon named Hakkar the Soulflayer. Hakkar would cast a spell called “Corrupted Blood” on players, which would slowly whittle down their health.

The effect of the spell was only supposed to last inside the raid arena—when players returned to the main world of the game, the spell would dissipate. But thanks to a software glitch, that wasn’t the case if the player had a pet companion. When the pets returned to the main world, they started infecting players and non-playable characters with the Corrupted Blood spell. If the player wasn’t powerful enough to heal themselves, they would die and erupt in a fountain of blood before turning into a skeleton.

What followed was a virtual pandemic that startlingly resembled today’s COVID-19 pandemic, from the spread, human behavior, and cultural response. Blizzard, the developer of the game, wanted players to social distance. Some players listened, but others flouted the rules, traveling freely and spreading the disease with them. Conspiracy theories formed about how the virus was engineered by Blizzard on purpose, and others placed blame on players with pets as the cause of the outbreak, mirroring the racist anti-Asian attacks and rhetoric surrounding COVID-19 today. 

Coincidentally, two epidemiologists, Nina Fefferman and Eric Lofgren, were there to witness the World Of Warcraft outbreak unfold. They studied and used the incident to model human behavior in response to a pandemic. Their findings were published in The Lancet in 2007. Many of their observations came to pass in 2020 when COVID-19 appeared. 

SciFri producer D Peterschmidt sat down with Eric Molinsky, host of the podcast Imaginary Worlds, who reported this story for his show. He talks about the epidemiologists who studied the outbreak and how it prepared them for the public responses to COVID-19.

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Segment Guests

Eric Molinksy

Eric Molinsky is the host of the podcast Imaginary Worlds.

Segment Transcript

JOHN DANKOSKY: This is Science Friday. I’m John Dankosky. Ira Flatow is away.

When the pandemic hit last year, people reacted in different ways from complete denial to volunteering to help others. Some people flouted the rules while others didn’t leave the house, and some even used it as an excuse to hurl racist insults and physically assault other people. These actions may have seemed unpredictable, but a group of epidemiologists was not surprised. They’d seen this all play out in another pandemic in 2005, one that happened online in a video game called World of Warcraft.

Players there became infected with the virus due to a glitch in the software. SciFri producer Daniel Peterschmidt is here to talk more about that. Hey, Daniel.


JOHN DANKOSKY: So briefly, what is World of Warcraft for those who don’t know?

DANIEL PETERSCHMIDT: Yeah, it’s one of the biggest online multiplayer games of all time. It’s been around since 2004, and basically you’re playing in this huge medieval fantasy environment with millions of other people across the world. You can play as an orc, a mage warrior, that kind of thing so kind of D&D stuff. And you can explore the world and fight monsters and go on quests with other people.

JOHN DANKOSKY: I’ve heard about it, never played myself, but it does sound pretty cool. So how did this all start with the epidemic in the game?

DANIEL PETERSCHMIDT: Yeah, so in 2005, Blizzard, the company who makes World of Warcraft, they created a new challenge, and basically it was you go to this one area, you battle a big villain, which is called a boss, this big snake demon thing that would cast a spell on you that gave you a kind of infection. And this infection was called corrupted blood, and the spell basically just slowly sapped your health away while you were fighting it. It would obviously affect you in battle, but once you defeated the boss, you could like go out into the main world and you’re basically not infected anymore.

JOHN DANKOSKY: So individual players could get infected while battling the boss, but then how did it spread to other players?

DANIEL PETERSCHMIDT: Great question. So there was a bug in the software where if you had a pet with you– you can have these companion pets– your pet would also get infected. And when you left the area and went back to the main world, your pet continued to carry the corrupted blood infection, and it would spread it to other players and other characters in the game. And they would slowly die.

JOHN DANKOSKY: So this was basically a computer virus that was acting like a real virus?

DANIEL PETERSCHMIDT: Right. And this sparked the interest of some epidemiologists who happened to be playing the game at the time. And I talked to Eric Molinsky about this. He’s the host of a podcast called Imaginary Worlds, which is a show about how we create these worlds and why we suspend our disbelief. And he reported a story about this outbreak and how stunning virtual epidemics can teach us how to deal with real ones. And I started by asking Eric how the virus started to spread in the world, and he told me that in a virtual world, it spreads very easily and very quickly.

ERIC MOLINSKY: In the real medieval world, a plague would travel about as fast as a horse, but in this magical medieval world, you can teleport back to cities. And a lot of these cities have what we call NPCs, non-playing characters, so it could be like a shopkeeper or a guard or just townsfolk in the background. But they all got infected with this thing, so they were walking around infecting everybody else asymptomatically, which is also a very weird thing, which is not supposed to happen. And so that’s another way that the disease spread really quickly.

DANIEL PETERSCHMIDT: And did you have to be really close to them to actually get it like how it works with COVID?

ERIC MOLINSKY: Yeah. Yeah, you definitely need to be close to get to them. And also, the longer you play in the game, the more health and wealth you build up. So you could almost be like the NPCs where you feel it’s the equivalent of you have a cough when people get COVID and they say, oh, it wasn’t that bad. It was just like a mild flu. Or maybe somebody has access to very, very high end medicine.

It’s different from some of the lower level players, the people that just didn’t have the time to invest that much into their characters and build up all that health, and those people were just getting wiped out like crazy. And you would really get sick. You would just– a fountain of blood would come out of you. It wasn’t like you just turn into a skeleton and disappeared.

DANIEL PETERSCHMIDT: Yeah, that is pretty graphic. So this caught the attention of some epidemiologists, Nina Fefferman, who at the time was at Princeton, and Eric Lofgren. So they were gamers also? They were like also in World of Warcraft at the time?

ERIC MOLINSKY: Yeah, they were. What was fascinating to them was not exactly the way that the virus spread in the game as much as the way people reacted to it because as epidemiologists, they would often do models to try to figure out, well, how are people going to behave. And economists have talked about this lately, too, that for so long their mathematical models would assume that in any situation, people would behave what they would consider to be rationally.

And so with World of Warcraft, here’s a virtual environment where most of these characters are being controlled by real people, which meant that they could study the behavior in real time as to how people reacted in a situation like this. And it was really fascinating to them because they were reacting in ways that no mathematical model would have predicted.

DANIEL PETERSCHMIDT: Right. So, yeah, can you describe those reactions and just some of the amazing similarities to how that epidemic mirrored our real-life pandemic now?

ERIC MOLINSKY: Sure. So as I mentioned before, this subset of players who were inadvertently responsible for spreading the disease were hunters who their digital pets got infected. So there was a lot of scapegoating against these hunters. And it’s a much, much more serious situation in the real world, but there’s a lot of anti-Asian racism that immediately started when COVID-19 came to the US and is still going on today.

There were fake cures being spread about and just a ton of misinformation and conspiracy theories. People thought the company Blizzard had created it on purpose or maybe there was some disgruntled employee who had created it. It was very hard to get correct information in a sea of misinformation.

Another thing that was really interesting was that there were people that were good Samaritans, people with very high health points– people who had a lot of health and wanted to help use their go into infected areas and use magical spells to cure people, but very often they overestimated how healthy their characters were and then they would get infected.


ERIC MOLINSKY: And then this is a subject you’ve talked about before on the show Griefers. In this case, people that basically have very trollish behavior online– and there are people that would actually go up and try to infect other people, which doesn’t happen very often. You very rarely hear stories about that, but actually Blizzard wanted people to do social distancing. But in a video game where the whole point is that you get to interact with other people through their avatars, social distancing is not a fun way to play the game.

And there were just a lot of people that simply didn’t care, people who are flooding the rules. People were being jerks, and then the other people who are taking it very seriously were upset and were just saying you’re ruining the game for us. This is not a joke for us. And that kind of conflict in terms of how seriously do you take it, how much do you follow the rules, that had a lot of interesting parallels as well.

DANIEL PETERSCHMIDT: How long did the epidemic last in World of Warcraft, and how many players got infected?

ERIC MOLINSKY: It lasted for about a week, which obviously compared to what we’ve been through doesn’t sound like much. But– so at the time World of Warcraft had about 6 and 1/2 million players around the world and over half of them, about 4 million, were affected by the virus. So it was huge. You had to just escape to a virtual mountaintop and let your character just sit there for the whole week. If you go to your virtual cabin in the woods if you wanted to avoid this thing or just not log on, which obviously for a game company is disastrous.

DANIEL PETERSCHMIDT: Right. It’s like, oh boy, time to go to the top of the mountain, do nothing, my favorite game.

ERIC MOLINSKY: Exactly. I went to log back in and see if my character is still staring at the sky.

DANIEL PETERSCHMIDT: So the virus is spreading in the game. There’s unchecked spread. People are traveling all over the place, and eventually things like stop mirroring reality as I understand it. Because unlike reality, World of Warcraft has an all powerful game developer named Blizzard, right?

ERIC MOLINSKY: Yeah. This is the thing where you wish you were living in a virtual world. They took control of the whole thing. They first they tried to put in a bunch of patches to stop the virus, and that wasn’t working. And eventually they had to just reboot the whole system.

DANIEL PETERSCHMIDT: Oh. On a slightly different note, I wanted to play this clip from your episode where you’re talking to one of the epidemiologists, Eric Lofgren, about this wave of non-compliant behavior that popped up when our current pandemic hit and how they really weren’t taken by surprise by it.

ERIC MOLINSKY: And I think one of the things that we’re seeing in parallel is that a lot of people don’t take infection seriously if it is not personally a risk for them. So you see a lot of people talking about coronavirus and they’re like, well, I’m young, I’m healthy. The mortality rate isn’t that high for me, so why should I care?

And I think in the Corrupted Blood case, there was a lot of that similar thing where this is bad if you’re high level but it’s not all that big a deal. But the server is being destroyed by this epidemic. The economy has been crippled. Everybody, can we cooperate for a little bit and get rid of this is I think the important parallel there.

Yeah, it’s just incredibly important that epidemiologists are not taken by surprise. To some extent, obviously, there are surprising things about it, but it was not a complete shock to them. And I think because this began to lay the groundwork for epidemiologists to understand that people are not going to react like mathematical models, and it’s an important part of their messaging as well to the public is to anticipate that this is going to happen and, again, not be surprised by it.

DANIEL PETERSCHMIDT: Yeah, we’ve had quite a few epidemiologists on the show over the past year, and it’s almost like they have to be part medical scientist, part social scientist it seems like.

ERIC MOLINSKY: Yeah, they’re really inseparable. And, again, I’ve noticed economists over the years have been talking about this as well, that too often that they base things off of these mathematical ideas of what people will do and people are obviously a lot more complicated. And it’s ironic that what seems like virtual people, even though they’re controlled by real people, is what made them realize that.

DANIEL PETERSCHMIDT: Yeah. Do you know what the reaction was like to this paper when it came out and if it– and if the paper had any impact on the scientific community, especially when COVID started?

ERIC MOLINSKY: I can say it was huge. The paper– when the paper came out, it was huge. Eric Lofgren and Nina Fefferman gave a lot of talks. It was generally a very well-received paper. People were pretty fascinated by it, and it had a really fun element to it in terms of video game that I imagine a lot of epidemiologists papers don’t have.

DANIEL PETERSCHMIDT: So what do you take away from the story after you finished working on it?

ERIC MOLINSKY: Well, the thing that I really thought about a lot was what counts as human contact to some extent– it’s so interesting to watch these people interact virtually through this– in this virtual world because we’ve all been doing that over the last year. In a way, we’ve all become more like players in a video game where we have– even when you’re on Zoom, you’re constantly watching yourself on Zoom, and it’s like there is an avatar version of me that’s interacting in this virtual world. And I just– I feel like in a way the whole world has become more like the World of Warcraft over the last year. And I really began to see that coming when I worked on this episode, and so it’s played out exactly the way I thought.

DANIEL PETERSCHMIDT: Eric, thank you very much for taking the time to be with us today.

ERIC MOLINSKY: Thanks for having me.

DANIEL PETERSCHMIDT: Eric Molinsky is the host of the podcast Imaginary Worlds. You can download it wherever you get your podcasts. For Science Friday, I’m Daniel Peterschmidt.

JOHN DANKOSKY: Daniel, that’s a great story about what we can learn from these virtual worlds. We’ve got to take a short break here, and when we come back, don’t zone out on us here. We’re going to talk about daydreaming and why it’s so hard to do for adults. This is Science Friday from WNYC Studios.

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About D. Peterschmidt

D. Peterschmidt is a producer, host of the podcast Universe of Art, and composes music for Science Friday’s podcasts. Their D&D character is a clumsy bard named Chip Chap Chopman.

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