# human extinction by a virus

**URL:** <https://boards.straightdope.com/t/human-extinction-by-a-virus/698293>\
**Category:** Factual Questions\
**Created:** [September 12, 2014, 3:40pm UTC](https://boards.straightdope.com/t/human-extinction-by-a-virus/698293 "2014-09-12T15:40:28Z")\
**Posts on this page:** 2\
**Page:** 2

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**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\
**Post date:** [September 15, 2014, 1:17am UTC](https://boards.straightdope.com/t/human-extinction-by-a-virus/698293/21 "2014-09-15T01:17:35Z")

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We certainly can’t prove it to be impossible.

However, when we look at the history of disease, there hasn’t been anything that could accomplish an extinction-level outcome. Not even close. Even some of the diseases that we’re most afraid of only kill a percentage of victims. The black death only killed perhaps 25-50% of those infected. Diseases with higher kill rates tend to top out in the 90-percents. Killing 99% of humans is bad… very, very bad… but it still leaves 70 million survivors. In other words, we’d still be one of the most numerous species on the planet for our size.

Even if you engineer the disease, you’re just looking at such a diverse range of genetics, diets, habits, environments, etc. We’ve got people living with minimal human contact out in the wilds of Alaska, people who live on sail boats, people with household bomb shelters… I just don’t see anything getting all of them. Collapse of civilization, certainly, but not extinction.

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**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\
**Post date:** [September 15, 2014, 1:37am UTC](https://boards.straightdope.com/t/human-extinction-by-a-virus/698293/22 "2014-09-15T01:37:17Z")

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> [@Chronos](#):
>
> In a sense, there’s still a huge stockpile of smallpox vaccine, stored in the T cells of close to a billion people. Anyone who’s had the vaccine would survive, even if the rest of us are screwed.

Not necessarily:

> [@](#):
>
> Smallpox vaccination provides high level immunity for 3 to 5 years and decreasing immunity thereafter. If a person is vaccinated again later, immunity lasts even longer. Historically, the vaccine has been effective in preventing smallpox infection in 95% of those vaccinated. In addition, the vaccine was proven to prevent or substantially lessen infection when given within a few days of exposure. It is important to note, however, that at the time when the smallpox vaccine was used to eradicate the disease, testing was not as advanced or precise as it is today, so there may still be things to learn about the vaccine and its effectiveness and length of protection.

[http://www.bt.cdc.gov/agent/smallpox/vaccination/facts.asp](http://www.bt.cdc.gov/agent/smallpox/vaccination/facts.asp)

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