All the big 30-point symptoms near the center line are excellent at killing people off in job lots, although tricks like Pneumonia or Hypersensitivity can potentially be more effective in their specialized areas (As the descriptions state, Pneumonia is especially dangerous in cold areas while hypersensitivity is particularly dangerous in urban environments where exposure to various allergens is much more common).
I'm personally a fan of Coma because it also makes the disease harder to cure and Necrosis because it means that corpses still remain infective (which can be a big plus if you haven't infected everyone yet).
gaming.stackexchange.com/users/7864/Shadur
I personally usually go with these two in the middle here:
The two abilities are:
Total Organ Failure Coma
I'm not sure if these are the fastest ways to kill off a population but between them they'll usually result in a world population graph that looks like this (assuming the whole population was infected before you went lethal):
gaming.stackexchange.com/users/52800/kalina
This is a good method: Wait until everybody is infected (a message will pop up saying "There are no healthy people left").
If you use a Bio-weapon, go to step 11,if not, go to the next step.
Evolve Coughing, Sneezing, Pulmonary Fibrosis and Total Organ Failure -
this is your main symptom (you can devolve Coughing, Sneezing and Pulmonary Fibrosis for extra DNA points).
If cure progress is over 80%, go to step 6, else go to step 5.
You don't need to worry about the cure.
Instead, evolve better symptoms : Hemorrhagic Shock - very lethal (evolve Anaemia, Haemophilia and Internal Haemorrhaging) Necrosis - very lethal (After Hemorrhagic Shock) Tumours - doesn't increase severity, but is lethal (after Haemophilia) Internal Haemorrhaging - quite lethal (after Haemophilia) Systemic infection - quite lethal (after Tumours) Immune Suppression - quite lethal (after Sneezing) Dysentery - quite lethal (after Diarrhoea) Get Insomnia and Paranoia (slows research).
Get Seizures (after Paranoia) and Insanity (after Seizures)
- reverses cure efforts.
Devolve Seizures if you want.
Get Coma and Paralysis - slightly lethal and reverses cure (after Total Organ Failure).
If the cure still builds up get Genetic Reshuffle in the Abilities section.
Get some of the good symptoms from step 5.
Get the Annihalation Genes (In Abilities) -
Completely fills the Lethality bar (after all 3 of its main abilities).
Watch the world die!
gaming.stackexchange.com/users/94116/Osome Oli
I just play with transmission, not symptoms, until everyone is infected, then evolve Anaemia, Haemophillia, Internal Haemorrhaging and the next one up.
Costs around 70-80 points altogether
gaming.stackexchange.com/users/124999/P. de Phile
I usually start with something like coughing and sneezing.
After like 80% of the world is infected, evolve immune suppresion and when 90% is infected total organ failure and coma.
Now, you see how the world is doing.
Cure is going too fast?
Coma>
Paralysis>inflammation>
Paranoia(Can also pick up insomnia as well)>Seizures>Insanity.
Need more lethality?
Coma>
Systemic infection>
Tumors>
Internal hammeorging> Hemmrotic shock>
Necrosis.
If everybody is dying too quickly, Immune suppresion>Fever>skin lesions>Necrosis.
When the pop-up that says(THERE ARE NO HEALTHY PEOPLE LEFT IN THE WORLD)appears, coughing and sneezing can be devolved for extra dna points.
gaming.stackexchange.com/users/250600/Mr. Baymax
With no bonus genes, using bacteria..not that that matters I think, starting in India on Brutal.
Water 1
Air 1 Drug Resist 1 Water 2 Air 2 (Whatever the air and water combo is)
Cold resist 1 Drug resist 2 Cold resist 2
Hardening 1 Devolve mutated symptoms until everyone is infected.
You should not have to pay for any of the downgrades.
Once everyone is infected, devolve two skills in transmissions, and the two cold resists from the abilities tab.
Go to your symptoms and starting with the bottom left one, go straight diagonally to the right and go up one...
ends with total organ failure
and then I added my left overs into seizures.
You shouldn't have any issues.
Watch your points, and just pump them into going to the right, so you can get the internal hemorrhaging, tumors, etc.
I also added the dysentery, first, before I went right.
gaming.stackexchange.com/users/125961/James
After a bit of practice I am now easily getting to a point where my plague infects the entire planet.    I am finding that with symptoms like Total Organ Failure and Comas that my plagues have a medium level of lethality and while everybody seems to die off pretty quickly I was wondering if these two are in fact the quickest way of killing everybody off.  So, now that everybody is infected with my plague - what is the quickest way to kill everybody off?
What is the quickest way to kill everybody?
gaming.stackexchange.com
<plague-inc>
gaming.stackexchange.com/questions/165888
gaming.stackexchange.com/users/52800/kalina
Coma makes the disease harder to cure and Necrosis means corpses still remain infective. Tricks like Pneumonia or Hypersensitivity can be more effective in specialized areas. There are plenty of ways to kill everybody in plague inc. Few common tactics involve  the usage of total organ failure and coma.
Players offering some advices.