As the Left 4 Dead 2 demo recently illuminated, some survivors in Valve's zombie-filled world are actually "carriers," people who can transmit the supposed zombie virus but are immune to the infection itself.
After a full five minutes of research, I have come to the conclusion that Bill, Zoey, Francis and Louis may, in fact, fall under this category. As much as we all love these four survivors, is it possible that with every step toward safety, they are unknowingly spreading the infection further?
Though nothing is certain and I fully hope that I am wrong, more evidence points toward the original survivors as infection carriers than I would really like to admit. By blasting their way through an infected wasteland, have the fearsome four actually made the world worse?
Hit the jump for our analysis.
The survivors are not, and cannot possibly become, zombies

Though we don't know for certain whether Left 4 Dead's zombie virus is airborne or transmitted by physical contact, we do know one thing: certain people, for whatever reason, are immune to it. The safe rooms writings in the first game make several references to "immunes," presumably to explain why, even after being bit and beaten and vomited on by the rampaging undead, the four survivors never actually turn into zombies.
In the first saferoom of the Left 4 Dead 2 demo, we see the following message written on the wall:
"Why are they separating everyone"
"Some people are carriers"
"They're immune but they can spread the infection"
"Who told you that?"
"That's BS"
Though it's probable that not all immunes are carriers, one has to consider that a pretty significant number of the immunes in the L4D universe must be carriers to justify FEMA's CEDA's decision to quarantine a percentage of the southern population.
As they are most definitely immune to the virus, could Bill, Zoey, Louis and Francis also be carriers? It'd be impossible to argue either way, unless we had evidence of them interacting with other, non-infected, non-immune human beings.
Oh, wait. We do.
For whom the (bloody, rage-infected) bell tolls

(Image from Left 4 Dead 411.)
At the end of Death Toll's third level, the survivors come across a lone (and presumably unstable) survivor who has holed up in a church. Because he is an asshole, he rings the church bell to summon a horde of infected rather than let the survivors into the saferoom. After dispatching the horde, the survivors open the saferoom to find that -- surprise! -- the Church Guy has turned into a random special Infected.
The Left 4 Dead wiki has this to say about the Church Guy:
"If you either listen carefully to the church guy, or search through the sound files; you can hear him talk about how the last person he let in attacked him. This is the reason he locks you out and is constantly heard muttering "Better Safe than Sorry". This also explains why he turns into a Boss Infected and gives possible clues about how the infection spreads."
And that makes a lot of sense. But at the same time, one can't help but wonder -- why, in all the hours that passed between the Church Guy getting wounded by a member of the Infected, did he only turn into a member of the Infected just when our survivors happened to show up? Within less than five minutes of being in the presence of Zoey and the others, the Church Guy goes from a reasonably healthy (if batshit nuts) human being into a Smoker/Hunter/Boomer.
There are three possibilities for the timing of this event:
- It's a huge coincidence
- Louis, Francis, Zoey and Bill are carriers and either infected him through proximity, or merely hurried along the infection that was already coursing through the Church Guy's veins
- Shut up it's just a frigging game why are you over analyzing the plot
My money is on one of the latter two explanations.
"Zoey, just pretend they're all helicopter pilots"

If the Church Guy incident hasn't convinced you that the survivors may be carriers, consider the events that take place between the end of No Mercy and the beginning of Crash Course.
The survivors leave Mercy Hospital on a helicopter (yay!), but the pilot turns into a zombie midway through the flight (boo!), so Zoey shoots him and Francis spends the entirety of Crash Course making fun of her for it (yay!).
But why did he turn into a zombie? Before he landed, he was fine; once he got into an enclosed space with four survivors who may or may not be carriers of the infection, he turned into a zombie. I mean, yeah, this guy could have been bitten a few days previous and just happened to turn into a zombie five minutes after meeting our heroes, but hell.
Turn into a zombie after spending five minutes around me once, shame on you. Turn into a zombie after spending five minutes around me twice, shame on me.
So, what does all this mean?

If the survivors from the first Left 4 Dead are actually carriers of the infection, what does that mean for them? Nothing good, I have to assume: based on FEMA's CEDA's policy of quarantining carriers until they get pissed and decide to revolt (as implied by a note written on the loading screen for The Parish), the survivors will either infect every person they come in contact with, or they'll be captured and put in government quarantine.
Or they'll do something none of us are expecting and somehow they'll meet up with the L4D2 survivors in the third Left 4 Dead game, and it'll be super awesome and it'll be like The Jetsons Meet the Flintstones except good and you'll be able to have Francis and Nick be assholes to one each other and oh my god so cool.
Or the government will line them up against a wall and execute them by firing squad.
As for the helicopter pilot, in the L4D voice files he has lines left over from a scene that was cut from the original release, where he mentions that during his last drop-off he thinks he "got hit".
Now, to tell my friends and take all the credit for the idea...
@Technophile: All great things come in 3s, duh!
@TheDirtyHeadband: I believe you get the Outbreak achievement while playing versus, if you are vomited on by a boomer who has the achivement. When you then vomit on someone who doesn't have the achievement, it is earned.
linkplz
Still, though. Still.
Or maybe I read too much into things >.>
And the reason why these zombies don't bite the characters could be because they know they are immune, so a beat down is in order?
Everything, though, seems alot more organized in Nawlins, though...
First the Infected to be needs to come into contact with an infected (by biting in both cases) and then come into contact with a Carrier.
Not saying this disproves that the 4 survivors are carriers.
Also, in L4D2 demo, the boat driver picked the new 4 survivors up previously and is dropping them off, and he did not turn into a zombie. But one could argue he is also a carrier.
"15:57:39 -
Are there plans to bring back the original survivors? "They're not dead, so we'll see what happens with that." Laughter. "They're not undead either.""
Doesn't the church guy say something about being bit? I dunno
When its more open for discussion and debate it makes for a better game.
I like your idea Rev hopefully there will be a lot more combining in the 3rd L4D. Maybe you can choose a team of four to play in the campaign.
I wonder how long they will take to start a 3rd L4D?
I've all but convinced myself this is the truth of it.
Like in Zombieland when that hot college chick says that a man "tried to bite her", when in fact, he actually did, and surprise.
MY GOD. GET VALVE ON THE PHONE!!!
That would be awesome.
I literally just finished getting the L4D2 demo (and the sweet Bill Hat for TF2!), and I wanna see these messages for myself.
I never even thought of it like that. It's awesome cause I think Valve has stated that you can make your judgements of how everything might have happened.
Revealing a little more story in this kind of subtlety is cool. Just like TF2 recently did.
the only escape that didn't involve a 3rd-party was crash course's "anti-zombie van."
I think I remember in the book that he met a women that was infected but not turned but would pass it on if she came in contact with someone that only had a resistance to the airborne virus, so she was like the L4D survivors if it's true.
But that's actually a really sad twist that the L4D survivors may unknowingly be killing those that help them.
But if not the game is still a classic
Nobody is saying you're right. This is all speculation.
First, the helicopter pilot. It is said, in one of the dev commentary that they wanted to have cinematics in the game to tell the story, but they realised that they would break the pace of the game. They take the example of the helicopter pilot being bitten and turning into a zombie after picking up the survivors. And during one of his radio communication in the game, he DOES says that he had "a little incident"... Check it out, I think it's one on the top of the roof of the building where you start. However I need to point out that I did NOT play Crash Course (560 MS points? Not happening), so they might be informations I'm not aware of that might happen during the playthrough.
Secondly, the church guy. What do we know about him? That he has been bitten by an infected (Or rather a person that was infected but did not turn into a zombie immediatly), so we know is infected too. Now, remember some of the writing in one of the safe room (I think it's the one in the finale of Mercy Hospital), they talk about how long it takes to turn into a zombie. One says hours, an other one half an hour, and another one says 5 min (or something). So we know that the incubation time for each person is different (It would also explain about the helicopter pilot). In one of his monologue, if I remember correctly the church guy says something along those lines: "It's been two hours now... I've gotta be immune, I've gotta be immune". If we take into account the whole safe room stuff I talked about earlier, we can deduce rather safely that the survivors just arrived at the wrong time. Plus, it's rather unlikely that they would do something to a person who's already infected, especialy with the whole "HUEG METAL DOOR" thing.
Once again, I don't believe the theory of the original 4 to be carriers (actually I kind of like thinking that the carriers they talk about in the safe room of L4D2 are the original 4, though it's kinda silly), but your theories are just... lacking I believe.
same here.. I'm completely unconvinced that church guy is any sort of evidence that the survivors are carriers.
Exactly what is "infected him through proximity?" If the only possible contact is by a degree through the air as they never directly interacted aside from yelling at each other through a steel door, logically wouldn't the virus then be airborne. Bill even says, "Son, we're immune, we're tired, and there's Infected in the damn woods, now cut out the shit, and let us in!" during the crescendo event so I would assume unless the church guy was in an airtight plastic bubble, he would have long been exposed to the virus already had it been airborne.
I was under the understanding that the virus was a mutated strain of rabies. The cow caucuses even have skin removed from their faces, presumably for rabies testing in Blood Harvest. Perhaps people who have received a rabies vaccine at some point of their lives got lucky during the zombie apocalypse. I'd highly suggest checking this out for more theories: http://left4dead.wikia.com/wiki/Infection
If the zombies aren't killing each other (which they're not, obviously) doesn't it follow that they wouldn't kill any carriers? Maybe not.. just throwing it out there.
If it was already planned I'd expect one or two rare lines about carriers. Just so the Valve guys could be all like "we DID drop you a hint, you could deduct it" now. There were none.
However IMO its VERY likely that they will now retroactively make one of them or all of them carriers. Becouse as you pointed out it not only fits but more importantly is just totaly awesome.