Come on, this is silly. We haven't learned nothing over the last year. https://www.nih.gov/news-events/nih-research-matters/lasting...
It's also worth noting that's a study of ~200 people. Given then times we're in it's an excellent sign and possible reason for cautious optimism and I'm sure a larger scale study is much harder to pull off in the midst of the pandemic.
That said, I have yet to see a study on the rate of reinfection of any of the variants against people who had already been infected with the initial strain, and how well that is survived, etc.
I was under the impression viruses became less lethal because if they became more, they'd kill off their hosts and be less likely to spread.
There's a chance you get some super virus that becomes both more transmissible and lethal, but that is very rare (from what I can see).
Only if the lethality is negatively impacting their fitness. If it can spread to another host quickly, who cares if the previous host dies. There's no selective pressure against it.
Which is why Delta is scary. Not just because of the higher viral load, but new strains could be more lethal and still not be selected against.
And let’s not forget about Mareks disease, where a non-sterilizing vaccine is thought to have contributed to a massive increase in virulence, killing nearly 100% of unvaccinated chickens now vs causing mild disease decades ago.
With a different presentation of disease where symptoms and spread occur concurrently then there would be a pressure on the virus selecting for strains that arent so lethal a carrier has no chance to spread. In covid’s case, that pressure doesn’t exist as far as i can see?
There are supposedly over 200 different viruses that can cause the common cold (https://www.nih.gov/news-events/nih-research-matters/underst...). So it's quite possible for immunity to any individual strain to last a very long time and still get multiple colds per year.
> Usually viruses become more transmissible and less lethal in response to rational behavior in their hosts--but humans are proving we're not rational.
Our own "rationality" doesn't matter much, if a virus leaves you bed-ridden or dead, that makes it very hard for you spread it regardless of your choices. The fact that we have so many different viruses which essentially cause more or less the same "common cold" proves that there is very strong evolutionary pressure for a virus to behave this way.
All viruses get less lethal as time goes on, not stronger, despite all the fear porn that has been indoctrinated into the public over the last year and a half.
But with C19 we are aggressively isolating people with symptoms. This focuses evolutionary selection pressure on the initial infectious stage. In order to be more infectious the virus increases viral load and shedding, causing more serious symptoms; which would be an evolutionary disadvantage, except isolation renders this disadvantage moot.
Also natural immunity general focuses on the nucleus of the virus, vaccine immunity is to the spike. So this forces mutations in different proteins, which has different results.
This isn't true. Given certain assumptions, it's true on average, but those assumptions don't apply in this case.
For a specific example the Spanish Flu hit harder later on.
Highly-deadly diseases will kill their hosts quickly, limiting their spread. Therefore, one of two things will happen:
• A less-deadly variant will emerge, spread faster, and outcompete its more deadly cousin.
• The deadly disease will kill enough of the population that its R number drops below 1, and thus the deadly disease will die out.
Therefore, observed diseases will tend to get less deadly over time.
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If you look at the data, we're firmly in “kill enough of the population” town (to the extent you can stretch this model to our situation). The variants we're seeing spread are getting more virulent over time, not less, because:
• we don't want to die and we're doing stuff about that, meaning any model with “most individuals infected are removed from the model” in it is a flawed model; and
• we have fast long-distance travel, so any population model that relies on Euclidean locality is a flawed model.
> Among five COVID-19 patients who were hospitalized, four were fully vaccinated
Wrong. It's generally the case, because a virus that keeps its host walking around will tend to infect more people than a virus that sends them straight to the morgue.
SARS-Cov-2 is unusual in that it's asymptomatic infectious period is really quite long. It's straight-to-morgue capabilities could become much more prevalent with hitting its infectivity too badly.
Smallpox.