Infection Mode Off: Surviving Project Zomboid Bite-Free
One-Sentence Snapshot
You can turn off infection in Project Zomboid B41/B42 by tweaking sandbox Zombie Lore settings (set Transmission to None and Infection Mortality to Never), or by using mods/cheats to cure or disable both the lethal Knox virus and regular wound/food infections.
Table of Contents
Understanding Infections in Project Zomboid
In Project Zomboid, "infection" can mean two very different things:
The Knox Event Virus
The zombie plague that turns you undead after a bite/scratch. By default, if a zombie bites you, it's a guaranteed game over (100% fatal). Scratches have a 7% infection chance, while lacerations have a 25% chance. Learn more about infection timeline and symptoms.
Regular Infections & Illnesses
Normal health threats like infected wounds, food poisoning, dysentery, etc. These can sicken or kill your character but are not the zombie virus and can be treated with proper medical care.
Types of Regular Infections:
- Wound infections (septicemia) â If you leave a wound dirty or untreated, it can become infected. Causes fever and health loss, but is treatable. See our wound treatment guide.
- Food poisoning â From eating rotten or uncooked food. You'll get Queasy and Weak moodles; severe cases can be lethal.
- Illness from corpses â Being around rotting zombie bodies can cause sickness. Curable with rest and proper nutrition.
- Mod-added diseases â Some mods introduce additional illnesses like dysentery, cholera, or other survival ailments.
Permanent Solutions: Disabling Zombie Virus Infection
Sandbox Settings Method (No Mods Required)
The simplest way to turn off the zombie infection is using the Custom Sandbox settings when you start a new game (or in server settings for multiplayer).
Under the Zombie Lore section, adjust these two critical parameters:
- Transmission â Set to "None" (sometimes labeled "Never" in older versions)
- Infection Mortality â Set to "Never"
Pro Tip
Another preset option is "Everyone's Infected" mode. In sandbox this is Transmission = Everyone's Infected, which mirrors The Walking Dead style lore. In that mode, everyone already has the virus, so bites don't cause zombification (no additional infection to catch). You only turn if you die from any cause.
Sandbox "Zombie Lore" options with Transmission set to None and Infection Mortality to Never
Editing Config Files (Server & Advanced Users)
If you're running a dedicated server or want to change an existing save's settings, you can edit the sandbox config file directly:
-- In Servertest_SandboxVars.lua or SandboxVars.lua Transmission = 4, -- 4 means None InfectionMortality = 7, -- 7 means Never
Trade-offs & Gameplay Impact
Removing zombification does change the game's balance:
Pros
- No more one-bite game overs
- Better for co-op play
- Great for long-term building projects
- Less frustration from unlucky RNG
Cons
- Reduces game tension
- Makes combat less consequential
- Changes intended game balance
- Can lead to more reckless play
Alternative Options
- Use Transmission: Saliva Only so only true bites (not scratches) can infect
- Try mods that lower infection chance rather than removing it entirely
- Use "cure" mechanics to keep infection as a challenge, not a death sentence
Mod-Based Solutions and Cheats
Sandbox settings are great for a clean toggle of the zombie virus. But what if you're already mid-game and got bitten? Or maybe you want infection on, but with a chance to cure it? This is where mods come in.
Top Mods to Disable or Cure Zombie Infection
1. "Immune to Zombie Infection"
This mod simply makes your character immune to the Knox virus. You can still be bitten and injured (and even get regular wound infections), but you will not zombify from zombie attacks.
2. "Antibodies" Mod
A popular mod that adds a chance to fight off the infection instead of a guaranteed death. It simulates your immune system producing antibodies over time. With enough care, you might overcome the Knox infection.
3. "Dark's Zombie Infection Cure"
A mod for those who want a literal cure in the game world. Adds a rare findable item (a cure) that can completely cure the zombie virus, as well as a craftable antidote syringe that temporarily halts infection progression.
4. "Infection Threshold"
A more subtle tweak mod. Doesn't eliminate infection, but changes it so that not every bite is equal. For example, it might allow that the first bite or two you ever receive won't infect you, but subsequent ones will.
5. "The Only Cure" (Amputation)
This mod lets you perform amputation on bitten limbs. If you act quickly after a bite to your hand or arm, you can amputate that limb and if successful, the virus is stopped (at a significant cost).
Disabling Regular Infections & Diseases
Now, what about the other infections (wound infections, food poisoning, etc.)? Maybe you're fine with zombies being lethal, but you're tired of dying because you ate one bad chicken or because your character caught a cold.
Wound Infections:
In B41, if you kept a wound clean, you'd usually be okay. In B42, antibiotics were introduced to treat infected wounds â making wound infection more of a threat.
- Set Basic Injury Severity lower in sandbox settings
- Use First Aid Overhaul mods to configure infection odds
- Always boil bandages and disinfect wounds
- In B42, prioritize finding antibiotics
Food Poisoning / Sickness:
- Turn Food Spoilage to "very slow" in sandbox
- Turn Rotten Food Removal on
- Always purify water (boil it)
- Keep Lemongrass (foraged herb) on hand to treat food poisoning
- Note: B42 made food poisoning less lethal already
Debug Mode & Cheat Menu
Let's say you didn't turn infection off initially, and now your character has been bitten and is fading fast. If you don't have a cure mod already, you can rescue your character via debug/cheats.
Using Debug Mode:
- On Steam, right-click Project Zomboid > Properties > in Launch Options type
-debug - Alternatively, while launching the game, hold LShift to get the debug mode
- In-game, you'll see a new bug icon at the bottom-right. Click it to open the debug menu
- Go to General Debuggers > Player or Health
- Toggle God Mode on briefly to instantly cure all illnesses, including the Knox infection
Debug menu with God Mode enabled to instantly cure infections
Using Cheat Menu Mod:
If the built-in debug is not user-friendly enough for you, there's a mod called "Cheat Menu" (and its updated fork "Cheat Menu Rebirth").
- Install the mod via Steam Workshop
- In-game, right-click to access the "Cheat Menu"
- Look for options like "Heal Whole Body" or "Toggle God Mode"
Important Note
Using debug mode or cheat mods will mark your save as "cheated" (you won't get achievements after turning it on). Always keep backup saves if you plan to tinker with debug or heavy mods.
Build 41 vs Build 42 Differences
Build 42 (currently in unstable/testing as of early 2025) introduced some tweaks to infection mechanics. Here are the notable differences:
Build 41 (Dec 2019 Stable)
- Set infection chances: 100% bite, 25% laceration, 7% scratch
- Added detailed Sandbox options for Transmission and Mortality
- Regular wound infections generally recoverable with time and care
- Food poisoning could be lethal if untreated
- No antibiotic items in the game
Build 42 (2025 Unstable)
- Same base infection chances, possibly higher in practice
- Added Antibiotics as a new item to cure regular wound infections
- Wound infections potentially more dangerous if untreated
- Food poisoning effect halved (2:1 ratio), making it less lethal
- Still no official cure for Knox virus (zombification)
Antibiotics in Build 42
Build 42 added Antibiotics as a critical item for treating regular wound infections. If your wound gets infected, you may need these pills to recover fully. Make sure to loot pharmacies early or adjust loot settings to spawn more if this proves too challenging.
Bottom Line
Build 42 is a bit tougher on illness but a bit gentler on food poisoning. The zombie virus remains as deadly as ever by default. All the methods we discussed (sandbox settings, mods, debug) apply to both B41 and B42. Just double-check mod compatibility; many mod authors have updated their infection-related mods for B42 or marked them as compatible.