New variant from South Africa

[Ferris]

Friend of mine has gone from testing negative to positive back to negative in 5 days. I think he still has to quarantine (I don't know the rules in Ireland) but we'll add another datapoint to my useless anecdotal dataset re: omicron being milder/faster to shake.

[JaDanketies]

Viruses 'want' to survive, replicate and spread, which favours those that evolve into less deadly and more transmissible forms. For an argument ad absurdum, a virus that killed 100% of people in seconds would not be able to survive or replicate very much.

COVID will have even more pressure to become low-symptom and less-deadly. Nowadays, the majority of people are testing themselves for COVID the moment they get a cough or any symptoms, and then aren't going out if they test positive.  A variant of COVID that can go more under-the-radar will outcompete it, because more people will go out and spread it.

Spanish Flu was eventually outcompeted by a less deadly version of the flu, after two years.

Here's something that was at the top of Google about it

"If you think about the way viruses behave, biologically, their reason for living is to replicate and spread, and there's really no advantage for the virus to kill the host," said Armitage.

What a virus wants to do is infect a host and be contagious so it can infect another host and it can continue to spread.

As part of this process, respiratory viruses often mutate and become less virulent and therefore less of a serious health issue.

[Zetetic]

One of the most notable features of COVID-19 in early 2020 was that it already had a period of asymptomatic transmission lasting a couple of days or more.

My question isn't "what's a selective pressure?", it's "what selective pressures apply to COVID-19 given its actual disease course?".

[JaDanketies]

My question isn't "what's a selective pressure?", it's "what selective pressures apply to COVID-19 given its actual disease course?".

Yeah it's still new and any guesses we make about the future of COVID and its likely evolutionary pressures are just reflections of what has happened in history, and don't take the specific features of COVID into account. Same way you can say "this Bitcoin is a bubble that is surely going to burst, just like the tulips," but really Bitcoin has very little in common with tulips.

[TrenterPercenter]

Friend of mine has gone from testing negative to positive back to negative in 5 days. I think he still has to quarantine (I don't know the rules in Ireland) but we'll add another datapoint to my useless anecdotal dataset re: omicron being milder/faster to shake.

My positive test this morning had a T line much weaker than when I tested positive 4 days ago so you can add this that to the scrap book also.

[greencalx]

Viruses 'want' to survive, replicate and spread, which favours those that evolve into less deadly and more transmissible forms. For an argument ad absurdum, a virus that killed 100% of people in seconds would not be able to survive or replicate very much.

The point is, I think, that many viral infections can be spread long before the host carks it, and there is no way the virus can 'care' about that at the time of the initial mutation. If there is an anti-correlation between transmissibility and deadliness, in general (and people I trust seem to speak as though this is a real thing), then my suspicion is that the explanation has more to do with physics (i.e., constraints on the way viruses can work) than evolution.

[JaDanketies]

If COVID makes you bedbound then it's not going to infect as many people as it would if you're well enough to go to work.

[Crenners]

Hiya April 2020 mate

[Ferris]

The point is, I think, that many viral infections can be spread long before the host carks it, and there is no way the virus can 'care' about that at the time of the initial mutation. If there is an anti-correlation between transmissibility and deadliness, in general (and people I trust seem to speak as though this is a real thing), then my suspicion is that the explanation has more to do with physics (i.e., constraints on the way viruses can work) than evolution.

Yeah it's the transmissibility that's key to a variant outperforming the other strains as far as I understand it: on a macro level, I can see that "keeping you alive longer = more transmissibility = dominant strain" so weaker ones might be primed to outperform the others, but there's no reason why it shouldn't kill you anyway (but take a little longer to do it which I suppose would technically be "milder", but hardly "mild").

It's a virus not a dinner party guest - it can treat its host however it likes on its way out the door.

[greencalx]

If COVID makes you bedbound then it's not going to infect as many people as it would if you're well enough to go to work.

I think you're missing the point about timescales. The question is whether it puts you in bed before you infect >1 person on average. If the answer is "no", you've got an epidemic.

In the long run, if variants A and B are equally transmissible, but B kills more people, then A will dominate eventually. But that takes time. What we're seeing here is (apparently) a milder strain that is simultaneously more transmissible, before selection has really had a chance to select on mildness.

[mothman]

I now have bread flour and yeast. Bagels may be in my future.

[Zetetic]

The point is, I think, that many viral infections can be spread long before the host carks it, and there is no way the virus can 'care' about that at the time of the initial mutation. If there is an anti-correlation between transmissibility and deadliness, in general (and people I trust seem to speak as though this is a real thing), then my suspicion is that the explanation has more to do with physics (i.e., constraints on the way viruses can work) than evolution.

I think it's rather that many viruses don't have this period of being asymptomatic but highly transmissible. COVID-19 is unusual, compared with many of the viruses that people cite in favour of this heuristic that evolution tends towards milder strains.

There are many viruses where person-level (rather than civilisation-level as we can imagine applies to the 'ViD) selection pressures seem more plausible, because you can isolate yourself or other people based on symptoms.

[Zetetic]

A tangent, but Ebola is an interesting one where spread often seems to be driven by a combination of its high lethality and its ability to spread easily from the dead.

I think such a high-level of post-mortem infectiousness is unusual. But again I guess it points to having to consider the actual specific mechanics of spread and disease course, if these don't fit the viruses you're basing your rules-of-thumb on.

[Ferris]

A tangent, but Ebola is an interesting one where spread often seems to be driven by a combination of its high lethality and its ability to spread easily from the dead.

I think such a high-level of post-mortem infectiousness is unusual. But again I guess it points to having to consider the actual specific mechanics of spread and disease course, if these don't fit the viruses you're basing your rules-of-thumb on.

Fuck me, Ebola sounds terrifying.

[Crenners]

EBOLA-19 when 😂😂😂

[olliebean]

In the long run, if variants A and B are equally transmissible, but B kills more people, then A will dominate eventually.

How so? If someone with B infects as many people before it kills them as someone with A does before they recover, why would A dominate?

[TrenterPercenter]

I now have bread flour and yeast. Bagels may be in my future.

Pictures please @mothman


of the bagels, no anuses (yet, let me see how you handle a bagel ring first).

[greencalx]

How so? If someone with B infects as many people before it kills them as someone with A does before they recover, why would A dominate?

Right, yes. Bit of ambiguity re "equally transmissible" there. I meant with the same rate of transmission, so B infects fewer people on average due to having less time to do so. But the point about timescales still stands - if B gets to infect very nearly as many people as A, then it could take years for the competition to play out.

[TrenterPercenter]

It's a arms battle between immune systems and viruses.  Viruses are simple things with two elements their ability to invade cells (transmissibility) and their ability to control cells and infect others (which is related to their incubation and lethality).  If a virus is mild but shares similar genetic information as more lethal versions then peoples immune systems will evolve to reduce it ability to enter cells.  Being well enough to transport this virus around whilst infectious surely just increases this effect.

I think the fact that the new strain is not able to bind itself as well as before to the cells in the lower lung is very good news.  The selective pressures are the same here in that gradually people with delta are more likely to have clearer symptoms and be taken out of the population one way or the other (i.e. reducing the infectious capacity).


Probably.

[Ferris]

South Africa Says Its Omicron Wave Has Passed, With Few Added Deaths
Case counts in the country are down by 30 percent in the last week, researchers said, without a major spike in deaths.

https://www.nytimes.com/live/2021/12/30/world/omicron-covid-vaccine-tests

Nice.

[shoulders]

Yeah

[Dr Rock]

Q/ I never get ill. There are presumably viruses around all the time and I'm over 50 and can't remember catching anything since I was pre-teen. Do I have a great immune system or have I been lucky? If I have a great immune system am I less likely to get the covid?

[Ferris]

The regularity of those peaks is something, eh. Presumably that's due to lower vaccination levels? No idea.

[JamesTC]

Wouldn't the three later peaks be for the three more transmittable variants (Alpha to Delta to Omicron)?

[Ferris]

Wouldn't the three later peaks be for the three more transmittable variants (Alpha to Delta to Omicron)?

I'd guess so, yeah.

[TrenterPercenter]

Still testing positive day 6 : (

[Ferris]

Still testing positive day 6 : (

I tested positive on rapid tests until day 11 after exposure! I think lateral flows were positive for about a week total (days 4-11 after exposure).

[TrenterPercenter]

I was hoping I would test negative today and tomorrow and then would be able to actually do something with my remaining 2 days annual leave but obviously not going to be the case.  I'm delivering some training face to face in 7 days so I need to be negative by then.

[shoulders]

I'm delivering some training face to face in 7 days so I need to be negative by then.

Your audience will be more receptive to positivity.

Gerry Bardsey's 101 Tips For A Happier Healthier Life

[chveik]

The regularity of those peaks is something, eh. Presumably that's due to lower vaccination levels? No idea.

starting to think there's some kind of conspiracy going on, big pharma companies hoarding vaccines in the west while letting the virus roam free in the rest of the world, so that new variants emerge and they can keep making billions of profit.

or maybe there's no need for conspiracies, it's just capitalism doing its thing