Symptom Combos are special combinations of Symptoms (and in some cases Transmission traits) that can affect plague stats, as well as trigger special events which can slow or speedup 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. Also note that the list may not be complete.
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.
|Projectile Vomiting||Increases Infectivity|
|Walking Dead||Decreases Cure research rate|
|Profuse Bleeding||Slightly increases lethality, greatly increases infectivity|
Lowers productivity but draws attention to the plague.
|Public Defecation||Increases infectivity and draws attention to disease|
|Swine Flu||Slight increase in work needed for a Cure|
|Increases Severity, Infectivity, and Lethality.|
|Tank||Slight Severity boost|
|Spitter||Slight Severity boost|
|Boomer||Slight Severity boost|
|Walking Contradiction||Slight Severity decline||Photophobia, Cathemeral Shift|
|Runner||Slight Severity boost|
|Bath Time||Infectivity Boost|
|Assassin||Increases Ape combat abilities|
|Blind Genius||Increases Cure Production|
|Discovery Channel||Increases Ape to Ape transmission|
Increases cross-species transmission
|Red Ape Redemption||Increases Ape combat abilities|
|Rude Awakening||Increases Ape to Ape transmission|
Neurax Worm (Santa's Little Helper)Edit
|On The Naughty List||Decreases happiness||Gluttony|
|Ultimate Christmas||Increases happiness and infectivity||Digital Elf|
- The Boomer, Tank, Runner and Spitter combos are references to zombies from Valve's Left 4 Dead franchise.