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Firewall, vaccine, cleaner... Place various blocks to protect your CPU! Vaccine A is a sandbox defense game, filled with parody of various programs.
No offers tracked in EUR yet.
"Protect your CPU!"
Build firewalls to protect your CPU, and build vaccines to keep malwares away!
Protect your base with 200+ blocks, skills and upgrades!
Restore your HP in Cleaner, Generate code files with Notepad, Watch full map with Web browser...
Interact with various characteristic blocks!
Noturn, A'vast... Upgrade various vaccines to protect your base.
Earn exp every game and apply 60+ new perks.
Meet familiar NPCs!
Clippy, Rocky, Installation wizard... meet your old friends.
Do you remember them?
BOSS BATTLE! yes. i said boss battle.
Boss battle every 6 waves!
Fire everything you got!
Test new strategy with Creative mode!
Test various strategy and skills in Creative mode, where you can handle every settings!
Firewall spamming? Boss battle without vaccine tool? Or... make your own mini-game?
※Every programs and parodies appear in this game is made with pure respect, and no copyright issues intended.
90% positive reviews all-time · 2 peak players in the last 30 days.
Project: Vaccine A peaked at 2 concurrent players on Steam in the last 30 days (highest on Jul 16, 2026). The player chart on this page updates daily.
Create a free price alert on this page and KingsPrice will email you when Project: Vaccine A drops below your chosen price. The biggest discounts usually appear during seasonal Steam sales and publisher promotions — the sale calendar on this page shows the next confirmed event.
