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The theory for selection for a more infectious/less virulent strain is sound. The value in a theory is that it adequately explains what has already occurred AND it proves to accurately predict what will occur...Thso theory accounts dfor the ameliortion over time of such things as measles & mumps (deadly until a century or so ago, Rheuamtic heart & kidney disease (already in decline well before PCN was discovered), Black Plague and on and on...The theory predicted the course we've seen with CoViD (look up my posts after about 4/20).
The article referenced is not by a scientist, but by a journalist- people notoriousy dull of wit and willing to spread The Narraative.
Moderator cut: removed deleted quote
All decisions should be made on an idividual basis weighing the costs/risks/benefits.
Some people think the thrill of skydiving is worth the risk. Others don't.
In regards CoV & vax-- the numbers do not clearly favor one choice over the other.
Fortunately I'm not dull of wit and I know a writer from a researcher. The article she linked to was behind a paywall so I didn't bother to try and track it down. I don't think she was wrong but it may be a bit more nuanced
It has been more than two decades since the formulation of the so-called 'trade-off' hypothesis as an alternative to the then commonly accepted idea that parasites should always evolve towards avirulence (the 'avirulence hypothesis'). The trade-off hypothesis states that virulence is an unavoidable consequence of parasite transmission; however, since the 1990s, this hypothesis has been increasingly challenged. We discuss the history of the study of virulence evolution and the development of theories towards the trade-off hypothesis in order to illustrate the context of the debate. We investigate the arguments raised against the trade-off hypothesis and argue that trade-offs exist, but may not be of the simple form that is usually assumed, involving other mechanisms (and life-history traits) than those originally considered. Many processes such as pathogen adaptation to within-host competition, interactions with the immune system and shifting transmission routes, will all be interrelated making sweeping evolutionary predictions harder to obtain. We argue that this is the heart of the current debate in the field and while species-specific models may be better predictive tools, the trade-off hypothesis and its basic extensions are necessary to assess the qualitative impacts of virulence management strategies.
Last edited by Deserterer; 12-25-2022 at 08:46 PM..
You can ignore the headline which sounds bad but only means the med tested is not every effective at its intended purpose
The good news comes couple of paragraphs in when the author compared vaxed CoVid patients now w unvaxed patients earlier in the pandemic. The proof of the vaccine’s effectiveness is what is revealed in reduction of deaths between two groups
Good news and what was probably already known but another confirmation
I’m fully vaccinated and boosted, and have never gotten COVID, but this is an incomplete comparison to draw the conclusion you made. You would want to compare both vaccinated now and unvaccinated now to see how both groups compared to unvaccinated at the beginning of the pandemic (which was everybody). That would be “the proof of the vaccine’s effectiveness” I’m reduction of deaths.
Now the vaccines most certainly contributed to herd immunity, which very likely has contributed to milder strains in terms of morbidity (along with people getting infected/natural immunity) circling today.
But I don’t know for sure, based on the data you are interpreting, that a vaccinated person today is safer from death than an unvaccinated person. You can draw that inference based on the comparison you’re making.
That said, I’m fully vaccinated/boosted and will continue to get the booster whenever I can. I personally think the potential benefits outweigh the risks.
It has been more than two decades since the formulation of the so-called 'trade-off' hypothesis ....
??? Two decades? Try closer to 100 years. I myself independenty realized it when I first took a course in genetics and then later read that they had beat me to it by decades before that.
You quote one dissenting opinion based on lame logic and exceptions.
??? Two decades? Try closer to 100 years. I myself independenty realized it when I first took a course in genetics and then later read that they had beat me to it by decades before that.
You quote one dissenting opinion based on lame logic and exceptions.
I don't really have a dog in this fight, I was just posting information that I came across because I'm a bit skeptical of ecological absolutes. I thought it was worth posting another point of view since the matter does not seem to be as settled as you think. Perhaps you should take up your grievance with Samuel Alizon, who said that. He's an evolutionary ecologist and research director at the Centre for Interdisciplinary Research in Biology in Paris.
Then you can discuss it with the authors of the following, because they made the same mistake.
The virulence–transmission trade-off hypothesis proposed more than 30 years ago is the cornerstone in the study of host–parasiteco-evolution. This hypothesis rests on the premise that virulence is an unavoidable and increasing cost because the parasite useshost resources to replicate. This cost associated with replication ultimately results in a deceleration in transmission rate becauseincreasing within-host replication increases host mortality. Empirical tests of predictions of the hypothesis have found mixedsupport, which cast doubt about its overall generalizability. To quantitatively address this issue, we conducted a meta-analysis of29 empirical studies, after reviewing over 6000 published papers, addressing the four core relationships between (1) virulence andrecovery rate, (2) within-host replication rate and virulence, (3) within-host replication and transmission rate, and (4) virulenceand transmission rate. We found strong support for an increasing relationship between replication and virulence, and replicationand transmission. Yet, it is still uncertain if these relationships generally decelerate due to high within-study variability. There wasinsufficient data to quantitatively test the other two core relationships predicted by the theory. Overall, the results suggest thatthe current empirical evidence provides partial support for the trade-off hypothesis, but more work remains to be done
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