Could we create a genetically modified virus or bacteria (with inability to mutate into something dangerous for animals) that would quickly spread all over the planet and selectively kill most of the viruses that we train it against?

Are there any other potential methods we could use to do it safely (without any danger to living creatures)?

Is that something we could actually do with a few billions of dollars?

  • 2
    $\begingroup$ (1) Dollar is not a good benchmark of costs (gold-gram is better); (2) not all viruses spread through atmosphere; (3) Viruses are ecologically important; (4) beware of unintended consequences; (5) the most dangerous viruses (from human perspective) are those not adapted to humans: don't eat bats, don't work in slaughterhouses; (6) immunization is a viable (pun not intended) anti-viral strategy; (7) i can imagine air-cleaning (bio-)nano-robots scooping up viral particles . . . but not until the robotization of vacuum cleaners advances a bit (pun intended). $\endgroup$
    – user37894
    Sep 24 '18 at 11:10

No (or a bit more scientifically: very very unlikely)

There a couple of reasons why your idea would not work:

Viruses are not alive, so you can't really kill them. The only ways to get rid of all airborne viruses at once would be to either:

  • A) UV-sterilize the whole atmosphere (bad idea, good xkcd what-if question though) or
  • B) fill the whole atmosphere with something that replicates itself and consumes very small particles of biological material (oops, we released grey goo).

It's also not possible to create bacteria or viruses that can both spread quickly (which means it need to be able to grow / self-replicate) and is physically unable to mutate.
Mutations arise from errors in DNA replication, and DNA replication is never 100% accurate, you can reduce the error rate, but it will never reach 0, so mutations will always be possible. It's also impossible to predict the 'direction' of mutations so you can't exclude that they will be dangerous for humans either.

As other comments have already mentioned there are even more problems with the idea itself:

  • not all viruses are airborne, many reside in animal hosts, so getting rid of the airborne ones will not do much
  • many viruses are not pathogenic for humans but ecologically important, you will get an unknown amount of ecological impact
  • $\begingroup$ @Nicolai A baseball thrown near the speed of light should do it. $\endgroup$
    – Bryan Krause
    Sep 24 '18 at 18:34
  • $\begingroup$ @BryanKrause A baseball thrown near the speed of light would flash-vaporize and burn up in the atmosphere, thoroughly obliterating anything in its path for its arguably short existence. $\endgroup$ Oct 19 '18 at 17:39
  • $\begingroup$ @user1258361 That's the joke; Nicolai was talking about sterilizing the atmosphere and referred to XKCD's "what-if" series; the first in that series was titled "relativistic baseball" what-if.xkcd.com/1 $\endgroup$
    – Bryan Krause
    Oct 19 '18 at 17:43

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