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.
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