I've heard that the longer a virus is in a population the less deadly it becomes. Something about deadliness being selected out from generation to generation.

Had me thinking that with the speed of vaccine development for Covid-19 that the virus may no longer have time to settle into that more benign phase.

Is there any truth to this?

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    Where did you hear this? This site requires questions to demonstrate some degree of prior research, so citing a source for that statement would be a good place to start. Keep in mind that smallpox was known to the ancient Egyptians, and by the time it was finally eradicated in 1980 it still had a 30% death rate.
    – Carey Gregory
    Sep 8, 2021 at 19:03

1 Answer 1


Unfortunately, there's no rule about viruses getting weaker. In fact the original SARS-CoV-2 was less deadly than some of the newer variants. In any case, SARS-CoV-2 has pretty much run rampant around the world even with the development of vaccines.

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