When the carrier hits a survivor, there is a 10% chance that the survivor will become infected. With few exceptions, an infected zombie will become a zombie after a fixed period of time. This time period can be extended using the Green Inoculator.

There are three stages of infection:

  • Window period
  • Symptom period
  • Transformation

Window periodEdit

During the window period, an infected survivor will appear green to any zombie who views them. Additionally, infection can be seen by zombies in the player list and in the kill feed. This survivor, and other survivors, have no way of knowing with certainty that he is infected.

Signs of Infection in the Window PeriodEdit

While none of these are a guarantee, they may indicate that you are infected.

  • The carrier suddenly stops attacking you and/or retreats.
  • Zombies seemingly not wanting to attack you.
  • Zombies stating over the mic that you are infected. (Note that sometimes zombies will lie to cause paranoia among the survivors)

Symptom periodEdit

The second stage of infection alerts a survivor to their condition. A gasping sound mixed with a heartbeat can be heard, the screen temporarily but trivially blur, sound is momentarily dampened as if the survivor had their ears covered for a moment, and the hit point icon will change into an "infected" icon. You will no longer be able to use voice commands.

During this stage, other survivors are able to kill the infected survivor, if they accidentally (or intentionally) hit them. Additionally, this is the stage in which the Green Inoculator can be used, and this will prolong the period that the survivor remains human before transformation.


Shortly before becoming a zombie, a player will experience the same blurring, sound dampening, and heartbeat/breathing sounds. At this point, the survivor will become a zombie, although their player model will be the "Infected Survivor" rather than the Zombie model.

If you are infectedEdit

Being infected may sound like it sucks, but it gives you some options for things that normally wouldn't be good gameplay strategies, and may even be considered griefing (In fact, some may still be considered griefing, dependent on the server. Use caution, and don't ruin the fun for others)

Infection is a moral choice. Either you help the survivors in your last few seconds before coming a zombie, or use the infection to make your life easier as a zombie by hindering your former teammates.

If you want to help the survivorsEdit

  • Tell them you're infected, and allow them to kill you
  • Distribute your ammo and weapons
  • Go on a mad zombie killing spree
  • Run and grab ammo/weapons from dangerous places and bring it back

If you want to help the zombiesEdit

  • Fire off all your ammo to waste it
  • Take everything you can and run into zombie territory
  • Avoid running into other survivors to avoid detection
  • Stay with other survivors so that you can attack them as soon as you turn
  • Break barricades
  • Block objectives

How to tell if other people are infectedEdit

One of the best ways to prevent damage from infection is to kill off those who are infected before they can turn. If you see other survivors attacking each other with melee weapons, they are checking for infection, and you should consider doing this if your group has recently been attacked by the Carrier.

Signs that they definitely are infectedEdit

  • A survivor that drops dead after you shoot them (on servers with friendly fire off!).
  • Someone you cannot pass through if the server has collisions turned off.

Signs that they might be infectedEdit

None of these are a guarantee that a survivor is infected, but this behavior can be suspicious.

  • A survivor who has been hit by whitey.
  • A teammate who shows anything under Signs that you may be infected.
  • A player doing anything under If you want to help the zombies.
  • A survivor who states that they are infected.
  • A survivor seems to be "lurking" or "stalking" another survivor. They may appear to be doing something but in fact probably standing just out of reach to turn on you when least expected.
  • A survivor runs away when you hit them with a melee weapon (FF off). Note: take this one lightly, since most people's reaction to being hit with a melee will be to run away because a) they think you are telling them to leave or b) they think they might take damage.
  • A survivor who the zombies have stated is infected.

Other Notes about InfectionEdit

  • Servers can modify the infection rate to make it higher or lower, so depending on where you are playing, the infection chance may not always be 10%. On some servers, as well as Hardcore mode, pills have a chance to cure infection.
  • You cannot win a survival map while infected. In the event that only survivors are left and one or more are infected, the game will not end until all the infected have turned and one side has eliminated the other. On the other hand, you ---can--- win an objective map while infected, dependent on the map. Biotec, for instance, will not allow any infected survivors to be on the helipad when the helicopter lands, but survivors can still win if infected survivors are outside the helipad upon the arrival of the helicopter.