Symptom Combos are special combinations of Symptoms (and in some cases Transmission traits or Abilities) that can affect the plague's Core stats or climate resistances, as well as trigger special events which can slow or speed up Cure progression, or draw attention to the disease. All combos have an achievement associated with them.

Note that it seems to take a while for symptom combos to appear and take effect. Please also note that the list may not be complete. Please feel free to add to the list.


To achieve a combo, one must evolve two or more different symptoms. They range from two tier 1 symptoms to eight symptoms and two infections, so using them is a viable strategy for new players and advanced players alike. Also be aware that once a combo has been triggered, it is not reversible and remains in effect even if you devolve the traits that caused it to trigger.

Name Effects Symptoms
Projectile Vomiting Increases infectivity



Walking Dead Decreases Cure research rate



Profuse Bleeding Slightly increases lethality, greatly increases infectivity


Skin Lesions


Lowers productivity but draws attention to the plague.



Public Defecation Increases infectivity and draws attention to disease. Increases research speed.



Swine Flu Slight increase in work needed for a Cure. 10% increase in budget required for cure.






Livestock I

Livestock II

Name Effects                    Symptoms

Vampire Bat

Increases Severity, Infectivity, and Lethality.

Vampiric Hunger

Bat 1

Bat 2

Blood in the Air

Increases Severity

Cathemeral Shift



Tank Slight Severity boost

Anabolic Boost

Bone Dysplasia

Spitter Slight Severity boost

Naja Mortis

Enhanced Sensory Integration

Boomer Slight Severity boost


Liquefactive Necrosis

Cranial Dispersion

Severity Boost

Cranial Elephantitis

Air 3

Walking Contradiction Slight Severity decline PhotophobiaCathemeral Shift
Runner Slight Severity boost

Enhanced Motor Control

Engorged Quadriceps

Bath Time Infectivity Boost




Name          Effects                    Symptoms
Assassin Increases Ape combat abilities

Ape Rampage

Primal Awareness

Blind Genius Increases Cure Production


Neuro-enhancement 3

Discovery Channel Increases Ape to Ape transmission

Primal Hunt

Social Cohesion

Fly Magnet

Increases cross-species transmission

Hominidae Bridge


Red Ape Redemption Increases Ape combat abilities

Horseback Riding

Weapon Creation

Rude Awakening Increases Ape to Ape transmission



Zombie Panic Slows Research Speed

Subconjunctival Haemorrhage

Total Brain Death

Bat 2

Blood 2

Name          Effects                    Symptoms
On The Naughty List Decreases happiness Gluttony
Ultimate Christmas Increases happiness and infectivity Digital Elf
Red-Nosed Guide
Red-Suited Pilot

Symptom Combos in Plague Inc. and Plague Inc: Evolved.
AssassinBath TimeBlind GeniusBlood in the AirBoomerCarpe JugulumCranial DispersionDiscovery ChannelFly MagnetOn The Naughty ListOopsProfuse BleedingProjectile VomitingPublic DefecationRed Ape RedemptionRed RainRude AwakeningRunnerSpitterSwinefluSymptom CombosTankUltimate ChristmasVampire BatWalking ContradictionWalking DeadZombie Panic

Achievements in Plague Inc. and Plague Inc: Evolved.
Plague ProBottle SmasherContaminated PackageEvolve your diseaseInsane BoltOlympic SpoilerPeer PressureRMS Watch ListSTALKERs delightThe End PlagueTouchscreen TrashNo BrexitSoft BrexitHard BrexitBrutal BrexitUnlock Virus disease typeUnlock Fungus disease typeUnlock Parasite disease typeUnlock Prion disease typeUnlock Nano-Virus disease typeUnlock Bio-Weapon disease typeUnlock CheatsBacteria MasterVirus MasterFungus MasterParasite MasterPrion MasterNano-Virus MasterBioweapon Master ● Disease Master ● BrainzzzzBrown StreetsLong ShotOink oinkRed RainUh OhPatient Who?Plague in SpaceChinese Nuclear RetaliationRussian Nuclear RetaliationBingo!Lottery winner!Normal ShuffleMega-Brutal ShuffleAssuming Direct ControlTrojan HorseWorm FoodNeurax MasterOn The Naughty ListUltimate ChristmasFlash MobI'll Be BackNot Another Zombie GameThe Glorious DeadWho needs DEETZ Com: Enemy UndeadNecroa MasterBoomerIs it a bird?JawsRunnerSpitterTankTastyUse your headWalking ContradictionBreathe DeepHide and SeekTest This!Big BangDead EndNon StarterGetting ColderIt's a Trap!Revenge of OsirisDue DiligenceBanana SkinDon't Ask MeAn Ape is for Life...Apes. Together. Strong.Apes will Rise!Attack of the dronesDid I mean to do that?EvacuApeExterminApeFamily. Future.Film FanaticGo Simian-faecesGreat EscApeNo IdeaNot Just a Pretty FaceShouldn't Keep PetsSimian MasterThe Future is BrightThe TravellerApe's CreedBlind GeniusDo it like they doLike flies round...Not NecroaRed Ape RedemptionRude Awakening ● Home Sweet Home ● Heart of Darkness ● Batmobile ● Twilight Lied ● Van Helsing's Doom ● Blood Pets ● Purity of the Chosen ● Luck of the DevilVampire MasterSadomasochist ● Count Countula ● Dark KnightSilent but DeadlyDentist's DreamDiamond SkinUphill Ice SkatingPlague DogsMr. UniverseBlood Trumps All ● Evil is a point of view ● Welcome to HellmouthCarpe JugulumEssential VitaminsBat CaveRock BottomChiroptophobiaWatery GravePus ExplosionWolf PackI am your FatherMaking AmendsGreyscale ● Power Overwhelming ● Complete Artificial OrgansComplete Black DeathComplete Created EqualComplete Frozen VirusComplete Global WarmingComplete Golden AgeComplete Ice AgeComplete Mirror EarthComplete Nipah VirusComplete Pirate PlagueComplete Santa's Little HelperComplete Shut Down EverythingComplete SmallpoxComplete Sovereign DefaultComplete Swine FluComplete TeleportationComplete Unknown OriginComplete Volcanic AshComplete Who CaresComplete XenophobiaLava GodMr PresidentSuper Sparrow ● Scenario Master ● Artificial Organs (Plague Inc: Evolved only)I never asked for thisWho needs brainsCall PETAContagion CancelledWho needs ScienceOn The Naughty ListUltimate ChristmasGLaDOS Says HiSushi Crisis