3 ms·

> In a vacuum this isn't true: diseases will select to be more transmissible, that can mean less deadly, but not always, think HIV. Is there any evidence of di

> In a vacuum this isn't true: diseases will select to be more transmissible, that can mean less deadly, but not always, think HIV. Is there any evidence of diseases that have selected to be less deadly, aside from by killing all of its especially vulnerable hosts? As far as I can tell, this is naive optimism: the selection pressure for not killing your host is irrelevant if they're only going to be infected for a week or two anyway, and basically every mutation that's going to increase transmissibility is likely to be negative (increased viral load in infectious agents, immune escape, etc.).

QuarterReptile 5y ago
>Is there any evidence of diseases that have selected to be less deadly.. It sounds like you're asking for specific examples of pandemics that didn't happen because they weren't detrimental enough to endanger people. That category of respiratory viruses is often broadly described as "the common cold."
- murderfs 5y ago
  No, I'm asking for specific examples of deadly viruses that have become less deadly over time. Like, take smallpox as an example. It's probably been endemic in humans for thousands of years: what's happened to its mortality rate? It's still at 30%, and the reason it's so low is due to human adaptation: the native Americans were virtually wiped out by it.
  - QuarterReptile 5y ago
    > It's probably been endemic in humans It probably was endemic, as it was declared eradicated in 1979 by an effective vaccination campaign. More importantly, though, smallpox, as a complex DNA virus, had far fewer viable mutations. That fact, along with an apparent lack of non-human reservoirs, is probably why it could be eradicated.
sgtnoodle 5y ago
This article claims that was the case for H1N1, as well as the "common cold". https://www.gavi.org/vaccineswork/will-covid-19-evolve-be-more-or-less-deadly https://www.gavi.org/vaccineswork/will-covid-19-evolve-be-mo...

QuarterReptile 5y ago

>Is there any evidence of diseases that have selected to be less deadly.. It sounds like you're asking for specific examples of pandemics that didn't happen because they weren't detrimental enough to endanger people. That category of respiratory viruses is often broadly described as "the common cold."

murderfs 5y ago
No, I'm asking for specific examples of deadly viruses that have become less deadly over time. Like, take smallpox as an example. It's probably been endemic in humans for thousands of years: what's happened to its mortality rate? It's still at 30%, and the reason it's so low is due to human adaptation: the native Americans were virtually wiped out by it.
- QuarterReptile 5y ago
  > It's probably been endemic in humans It probably was endemic, as it was declared eradicated in 1979 by an effective vaccination campaign. More importantly, though, smallpox, as a complex DNA virus, had far fewer viable mutations. That fact, along with an apparent lack of non-human reservoirs, is probably why it could be eradicated.

sgtnoodle 5y ago

This article claims that was the case for H1N1, as well as the "common cold". https://www.gavi.org/vaccineswork/will-covid-19-evolve-be-more-or-less-deadly https://www.gavi.org/vaccineswork/will-covid-19-evolve-be-mo...