How to Turn Off Infection in Project Zomboid (Build 42.19)

Build 42.19 · Set Zombie Lore → Transmission → None to stop new Knox infection from attacks. Infection Mortality → Never is optional for the virus death timer.

What “turn off infection” means

In Project Zomboid, “infection” usually means two different systems. Sandbox Zombie Lore only controls the Knox virus (zombie plague). Ordinary wound sepsis, food sickness, and corpse-related illness are separate.

New world, existing world, emergency

Sandbox / server UI

Prefer the in-game controls when you can. They write the same sandbox values without hand-editing the server file.

Single-player custom sandbox

1. Start a new game with Custom Sandbox (or open sandbox options if your flow allows editing before start).
2. Open the Zombie Lore section.
3. Set Transmission to None.
4. Optionally set Infection Mortality to Never if you also want the virus timer never to kill.
5. Start the world. Mid-save exposure of these options varies; servers use the Host UI or the sandbox file instead.

Multiplayer Host / dedicated server

1. Open server settings (Host → Edit Settings / Manage Settings, or the dedicated panel’s sandbox editor).
2. Find Sandbox → Zombie Lore.
3. Set Transmission = None (core).
4. Optionally set Infection Mortality = Never.
5. Stop the server cleanly if it is running, then start it again so clients load the new sandbox values.

Edit <ServerName>_SandboxVars.lua

Use this when the Host UI is unavailable (remote dedicated box, scripted deploy) or when you need to set the exact field values by hand.

Where the file lives

• The directory is Users (with an s), not User.
• The file name is <ServerName>_SandboxVars.lua (for example servertest_SandboxVars.lua).
• If the server runs under a different system user or container home, use that user’s Zomboid/Server/ tree.

Safe edit steps

1. Stop the multiplayer server completely.
2. Copy <ServerName>_SandboxVars.lua to a backup (for example …_SandboxVars.lua.bak).
3. Open the file in a plain-text editor.
4. Find the ZombieLore = { … } block.
5. Set Transmission = 4. Optionally set Mortality = 7.
6. Save the file. Confirm braces and commas still look intact (a broken brace will prevent the server from loading the profile).
7. Start the server again and join with a test character if you can.

-- Inside <ServerName>_SandboxVars.lua (other ZombieLore fields omitted)
ZombieLore = {
    -- ...
    Transmission = 4, -- None: no new Knox virus from zombie attacks
    Mortality = 7,    -- Never: optional; already-infected do not die from the virus timer
    -- ...
},

Platform paths and multiplayer-only notes in more detail: Turn off infection (Transmission = None).

Transmission and Mortality values (Build 42.19)

UI labels and file numbers for Build 42.19. Indices start at 1. The Apocalypse preset uses Transmission = 1 (Blood and Saliva) and Mortality = 5 (2–3 Days).

Wounds, food sickness, Antibiotics

Debug emergency clear (already bitten)

Sandbox Transmission changes do not always rewrite a character who is already infected. For a local emergency save, debug tools can clear the Knox flag.

1. Steam → Project Zomboid → Properties → Launch Options: add -debug.
2. Load the save. Open the debug menu (bug icon / debug toolstrip).
3. Open General → stats/body tools.
4. Use the body toggles: uncheck Infected if present. You can also adjust a Zombie Infection slider when the panel exposes it.
5. God Mode is a separate invulnerability-oriented toggle. Prefer the explicit Infected flag when you only need to undo Knox.

Mods

Workshop mods can add immunity, probabilistic recovery, amputation, or crafted cures. Names change and forks often lag behind Build 42, so always re-check the Workshop page for your branch before installing.

• Search Steam Workshop for current Build 42 tags and recent update notes.
• Note Workshop ID, Mod ID, load order, and whether the mod edits infection chance, mortality, or only post-infection recovery.
• Prefer sandbox Transmission = None for a clean vanilla “no Knox spread” multiplayer baseline; use mods when you want partial risk or roleplay cures.
• Common categories: immune traits, antibody systems, rare cure items, amputation kits, configurable infection thresholds, and general cheat menus.
• For amputation-focused play, see The Only Cure — re-check Workshop compatibility for your build.

Gameplay impact

With Transmission = None, players stop treating every scratch as a potential soft-lock. Combat mistakes still kill through bleeding, fractures, exhaustion, and being swarmed—only the Knox infection channel is closed.

FAQ

Related guides

• Turn off infection (Transmission = None) — multiplayer paths and SandboxVars platforms.
• Infection modes explained — Transmission options and Knox vs ordinary illness.
• Server administrator tips — backups, sandbox, and day-to-day host tasks.
• First aid guide — wound care separate from the Knox virus.