Given our world's response time and action to major outbreaks of viruses that have happened in the past, how quickly would this virus have to spread to have a full on apocalypse where government and armies have been destroyed.

It may not even be a matter of how quickly, how would it spread at all without a government or army successfully destroying it?

  • $\begingroup$ Well that is what I am asking. What properties would be required to avoid our methods of destroying viruses. $\endgroup$ Jun 18, 2015 at 14:53
  • $\begingroup$ your question might be a bit broad, please consider at least which means the virus has for infecting. A tldr: if it can only infect by biting, then it wont propagate. If it has a incubation period, and can be transmitted person by person (preferably in some airborne way) during this period, then it will be able to reach the mayority of the world. My advise: play the plague inc zombie virus mode in the hardest mode. Plague inc is fairly realistic $\endgroup$
    – Silver
    Nov 25, 2015 at 19:44
  • $\begingroup$ Newsflesh has a good method An airborne cancer fighting virus that survives by blending into the immune system...that activates and reanimates a person after they had died as long as their brain is intact. Much like walking dead $\endgroup$ Apr 14, 2020 at 12:42
  • $\begingroup$ 2020 has kinda answered this for me. Turns out, our response time isn't that quick... $\endgroup$ Jul 31, 2020 at 13:59

4 Answers 4


Anything that increases the period where people are carries before combing a "zombie". If the infection does not activate until after someone dies. Then they have all the time while they are alive to infect other people. The quicker it causes someone to transform from normal to zombie, the more likely governments will be to survive.

Making the infection vector air born(increase infection routes). If it can survive for long times in the air, or on a surface then you multiply the opportunities for infection to occur.

Super bug. Make the infection/virus immune to the standard disinfectants. If we can not sterilize it, we can not stop it. (Model it after the pryons in Mad Cow/Creutzfeldt–Jakob disease)

Super bug mod. Make it so that certain sterilization technics act as a catalyst. People take the standard actions to sterilize, and instead make the infection more virulent.

There is a steam game where you play as the infection. A couple plays through of that might lead to other ideas.

  • $\begingroup$ "There is a steam game where you play as the infection" It's called Plague Inc. There's also a board game version (it's pretty good, but I suggest getting the expansion pack). $\endgroup$ Apr 14, 2020 at 12:45

The most important requirement is a moderately long combination of incubation/asymptomatic infectiousness. I've not run across many descriptions of zombies which would allow one to pilot a jet or a ship across an ocean, so global spread requires travel by the asymptomatic.

If the turned zombie only becomes infectious once she is obviously a shambling, rotting, brain-craving revenant, stopping the spread of the condition is likely to be pretty effective. The more victims the condition can infect without being detected, the better it will spread.


Newly infected should turn within a few minutes at most

The reason for this is to remove any ability of newly infected humans to react. If it takes many hours for a newly infected to turn from patient zero, then the virus will be easy to contain.

Lets say those bitten by patient zero take 2 hours to turn. At first, people may seemingly be murdered by patient zero, but very soon police will be called and the injured will be seen in hospitals. Police officers will easily put down patient zero. Those seen in hospitals will turn, but will be quickly restrained. I would expect any trained physicians to quarantine new victims bitten in the hospitals, thus stopping the infection there. As for those 'murdered' by patient zero outside the hospitals, it will not take law enforcement long to put down the 'murder' victims rising from the scene.

However, if patient zero is in a major population center, and his victims turn in a few seconds, then the cascade of zeds will exponentially increase, completely wiping out whatever continent it was on.

As for how the infection will spread overseas, that has to be left to you. Perhaps a terrorist organization collects some of the victims and unleashes them against their victims. Perhaps one zed strays onto a cargo boat as it's leaving port to safety on a new continent.

"Proof (this is fiction of course)"

Note how every single zombie story with a long (hour or more) period between bite and turn focuses on survivor drama, and starts out with everything 100% apocalyptic from word go. None of these shows or movies ever show from patient zero.

Zombie Land - We get flashbacks to before the outbreak, but no detail about how it's spreading.

Dawn of the Dead - The MC wakes up, everything's in chaos, and she takes refuge in the mall.

Walking Dead - The story starts when Rick wakes up; after the apocalypse.

Left 4 Dead - Story starts after the outbreak.

Dead Rising - People turn slowly, and the outbreak is contained to one town.

The only one that shows me a plausible apocalyptic spread is WWZ. And the newly bitten turn in 8-12 seconds.

  • 1
    $\begingroup$ Longer incubation is better for spread. So it can be spread unknowingly. Quick spread can be contained by shutting down transportation. Continents are not connected by uninterrupted population centers. Traveling at walking/running speed would take a very long time to cross the US for example. Meaning a defensive line could easily be put into place. $\endgroup$
    – House
    Apr 28, 2017 at 22:07
  • $\begingroup$ @MichaelHouse Yes, but at the same time the "2-4 hours" trope is pretty suboptimal; if it's a choice between "2-4 hours" and "8-12 seconds", "8-12 seconds" would win. $\endgroup$ Apr 14, 2020 at 12:51
  • $\begingroup$ But doesn't dawn of the dead start in the beginning of the outbreak, when the zombie problem was just starting? There were people on TV talking about how to stop dead people from rising and getting in arguments and stuff, the MC's coworkers are also making a run for it while they can $\endgroup$
    – Hi0401
    Dec 31, 2022 at 4:50

It really should spread quickly, but not so quickly that all the humans alive die out in a week. So maybe a year or 2 is good. Though 6 months is good, that would be very quick

  • $\begingroup$ Welcome to the site. You may want to edit your answer to add details, such as how your timetable relates to disease response time. The Worldbuilding SE strongly favors detailed answers and, barring additional information, this may be deleted as inadequate. $\endgroup$
    – Frostfyre
    Sep 27, 2016 at 12:10

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