3 ms·
SARS and HiV are certainly not examples where a human virus has evolved to become more contagious but less deadly. SARS was not contagious enough to escape our
by somewhereoutth 5y ago
SARS and HiV are certainly not examples where a human virus has evolved to become more contagious but less deadly. SARS was not contagious enough to escape our control efforts, and HiV is mitigated by our anti viral drugs.
Indeed it would be nice if a less severe strain out competed current COVID, but such a thing has never happened before (as far as we know) - and as you point out there is no selection pressure for mildness when death/disability occurs some weeks after the infection has been cleared.
- robbedpeter 5y agoThere are multiple strains of hiv. One of the papers I linked to is a detailed study investigating a less lethal, more infectious strain. Sars-cov1 also evolved a few strains that were more infectious and less lethal. Both effects, by the way, are usually associated with separate individual mutations. It's rare that a single change in DNA results in both effects.