The answer is part scientific, part administrative, and part practical.

Scientifically, the spike protein is made up of many different epitopes (smaller parts of the protein that are recognized by antibodies or T cells). Some of those epitopes still convey protection for current variants.

Administratively, Covid vaccines still have to go through hoops that eg influenza vaccines currently don't, so it's easier to just use what's already gone through trials and approval processes. Soonish, the vaccines can bypass those regs and update as fast as flu vaccines do. Whether that is helpful or not is up for debate, as we've seen that flu vaccines are often outdated by the time they're released.

Practically, if the vaccines are still effective, there's not a lot of pressure on eg Moderna or Pfizer to "retool" the production lines to make an updated vaccine.

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"Omicron and later" has huge variation. The variants people are getting now are as different to Omicron as the initial variant was from Omicron. They get named based on how concerning they are - they're Variants of Concern - not how different they are. So when they say "nothing works in a lasting fashion against them" it's because there are many of them.

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Very cool write up, especially learning how viruses tend to become less lethal and more contagious. It’s like the use us humans as the method for their life and once they reach their max potential it’s like oops yeah I didn’t mean to kill every one on the way

Is there any evidence that colds use to be more deadly and now they’ve reached a point that they’re largely contagious and less deadly?

However the original spike is included in the bivalent vaccines. What is the scientific justification for including the spike for extinct variants?

Edit: re: u/Tephnos why are extinct strains of flu not included in the flu vaccine then?

The other half of it is, Even though the batters started hitting instead of striking out, they're mostly hitting singles or doubles instead of home runs. So it's easier to prevent runs from being scored (in this analogy, runs are deaths)

Whenever a virus replicates, there is a chance for the new virus particles to develop mutations. If these mutations make them less contagious, they will quickly get outcompeted by the old lineage and die out. If the mutations make them more contagious, they will outcompete the other strains until they become the new dominant version that new mutations develop from.

The only upside is that viruses don't usually benefit from becoming more deadly; if anything, that makes them less able to multiply if they kill their hosts. (Exception: if the host becomes very contagious before dying to the virus, more lethal strains could still develop as long as they are able to successfully leap from person to person before their victims die.) So in the long run, many viruses tend to get more infectious but less lethal, since the mechanism that makes a virus lethal is usually complicated and most random changes to it from mutations tend to reduce severity, not increase it.

I read about the trials of figuring out how to use the bathroom in space were actually pretty terrible until they sent women to space. Basically they tried a number of solutions like condoms. Anyways all of them would usually result in getting covered in piss. When they finally sent women to space they decided on diapers being the best option, not long after that the men on the missions demanded their own diapers when they saw how easy the women had it. I've also heard from interviews with astronauts, there's a secret rule among them. never eat a floating chocolate.

Thank you for that perspective, it makes me feel much better about things. Not enough better to quit being careful, but still better than I had been.

You have to take into account what evading immunity can mean. It means it can infect people and they can spread it, it however doesn't mean they have a serious disease or need hospitalisation.

The issue with COVID-19 was lack of any immunity at all, while early variants infected the lungs, later, more infectious variants started to infect the upper airway more seriously, but the reality is while this allows more effective spread, the upper airway is largely irrelevant, it isn't what absorbs your Oxygen supply, it is just causes a really bad cough instead.

Then you have to take into account this issue isn't a disease existing, it is everyone getting it at the same time, and then a significant percentage needing hospitalisation at the same time. Imagine everyone broken their arm at the same time, A+E would collapse, orthopaedics would collapse, any requirement for surgery would be overwhelmed (it is needed in 2 weeks), there would be no ability to get people effective rehabilitation, and people would start dying from complications of broken arms.

That is essentially what happened in COVID, with "a broken arm" being an unknown disease with an unknown treatment pathway, which once again is a massive problem. It is fine if you can treat 95% of your patients with X known treatment, it is another thing when you are trying to work out what treatment is needed, then when you do, don't have the equipment to implement it, or the specialists to manage it.

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A common rule of virus evolution is that viruses tend to evolve to be more contagious and less deadly. The rationale here is that a dead host is not a viable vector for contagion, and if your strain kills the host, then the strain dies along with the host body.

As a result, strains that keep people in contact with each other rather than isolated at home or in a hospital are going to be way more successful and will outcompete each other, and it goes without saying that of course the more contagious the virus is generally, the more successful it is as well.

how will it become a white dwarf during proton decay? isn't that the phase when all stars die?

Transmission wasn't halted because the vaccine doesn't produce great mucosal immunity since so the virus easily and quickly replicates and is able to be spread, vaccine does great against more moderate and severe disease, which takes days and weeks to develop.

That's more like saying relativistic effects mean that any matter that fell in less than infinity years before you is going to be between you and the actual singularity. It's not that the neutron star is 'in' there, it's that it can't ever finish falling in before you catch up with it's trailing edge...I think?

Kinda way out on a limb there. Can anyone help out if that's totally wrong?

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There's a significant concern that Alpha or Delta could be hiding out in an animal reservoir, for example white tail deer.

https://www.pnas.org/doi/10.1073/pnas.2215067120

Anything that emerged would be quite distant from the earlier variants, having evolved in animals for years. But if it still has a human compatible spike protein, that would be bad. Omicron's spike changed drastically in isolated evolution; it wasn't competing against other circulating viruses. Omicron proved very fit.

The primarily barrier to zoonotic disease is that they aren't efficient at going after human receptors. Something that was adapted to humans first is potentially dangerous.

Some derivative of it likely does, but it's been eons (in viral time) since delta was first identified, so almost without a doubt it has continued to evolve in those reservoirs - much like mammoths have gone extinct but we still see their close relatives in elephants. For the time being, anyway.

The old variants would have continued to mutate as they spread, they won't resemble them much. But, we still have a bit of a COVID problem.

The hospitalization rate for COVID may be in a valley right now, but look at that 'valley' in some countries. In Australia, it is just a bit below the Delta waves PEAK. We still have concerns about T cell damage and illnesses in general taking longer to get over due to this damage... I would keep up on epidemiologists sharing data online, and monitor their findings for anything alarming.

Omicron isn't a single serotype (immune recognition), it's actually a ton:

https://covid.cdc.gov/covid-data-tracker/#variant-proportions

So this isn't waning immunity, it's serotype emergence that escapes immunity.

ELI5: we get a great pitcher versus the first batter but they keep changing batters as we strike them out until eventually our pitcher is terrible. Then we bring in a new pitcher to match against the best batter we've seen so far and it starts all over again.