I know that some people here have medical / scientific backgrounds and have been kind enough to educate us, so I have a question:
Can anyone explain the science behind the new variants? Does-it happens randomly? Are those like mutations in genes? I have a ‘friend’ who spreads non-reliable information saying that ‘they’ are just finding new excuses to keep us in our houses and justify closing the schools. Schools are still open in France but the UK variant is prevalent and I heard about a South Africa variant in someone coming back from Zimbabwe. We have a curfew at 6PM but if it’s not enough they might close the schools so people are freaking out. While I know she’s not right and it wouldn’t be reasonable to engage, I’d like to understand more how this happen so that I can discuss it from a scientific position. Also can the vaccines protect from those variants?
RNA viruses make mistakes almost every time they replicate their genome inside a cell. Maybe just a few base pairs here and there, but they’re not great at proofreading the final product. Over time, if those changes are maintained, they can eventually cause small changes in protein expression.
From what I have read, though, the mRNA vaccines are based on the coding sequence for the spike protein, which is the protein that binds to human cells so the virus can infect them. That’s a very important protein, and is likely to be well-conserved (if it changes too much, it might not bind as well/be as infective), so the vaccine will probably continue to be effective. Since the protein itself is expressed in our cells after the vaccine, we make antibodies to multiple sites on the spike protein, too, so immunity would be even more well conserved.
So far, the vaccines can protect from the variants, because what it targets does not appear to have mutated
Variants are expected. Everytime the virus replicates, it has a chance to mutate. Just like when people have a baby…sometimes things are different than they were before. Evolutionarily, viruses “want” to mutate in a way that will best preserve themselves…so something that spreads quickly, and also usually something that doesn’t kill it’s host too fast, because if they do that, it won’t spread.
We are seeing so many variants because the spread of the virus is out of control. So many people are becoming infected which gives the virus more chances to mutate. Successful mutations spread. Unsuccessful ones don’t.
The US apparently has two new variants in Ohio that seem to have started here.
Think of the variants kind of like the flu…there are SO many variants of it. But it’s vaccine works differently so they have to guess which variants will be dominant in any season.
I just want to add one thing to this - the flu vaccine is based on the combinations of hemagglutinin and neuraminidase (two surface proteins) subtypes that are predicted to be most common in any given year. Influenza A has 18 H and 11 N varieties. There have been 131 detected subtype combinations since they started tracking, and there are 198 possibilities. Making a vaccine against that is SO much harder than against a virus with a single spike protein, but we still do it.
Thanks for explaining that. It makes much more sense and it is reassuring.
Okay so that’s why those new strains (at least the UK one) spreads so fast and do not appear to be more agressive.
Well this is fascinating and certainly amazing that we can make a vaccine effective against so many strains. So we should hope that the COVID-19 spike protein doesn’t mutate. Do we know if the flu started with one binding protein too? What I mean to ask is whether it is a possibility for this spike protein to mutate one day?
I honestly don’t know about the flu. The 1918 influenza epidemic was an outbreak of H1N1, so at least as far back as that it’s been the same.
We only make vaccine against the three or four combinations that are predicted to be the most common in a given year, based on what they’ve seen throughout the year, and vary based on which hemisphere you’re in, I think. That’s why it’s more effective some years than others - their predictions are wrong. It must be a really difficult job. “We’re picking…these 3, out of the almost 200 options we have. Good? Sounds good!”
Got it. Thanks for explaining it clearly. It’s the closest I’ve come to understanding how it works. There are so many evolving statements out there that I don’t google those subjects anymore.
Thanks @anon51297825 for your reply too. I’ve learned a lot. I’ve seen everywhere that variants are to be expected and the vaccine should be effective but I didn’t grasp why and how.
My husband (who does this thing…like he makes DNA) was saying that as the first mRNA vaccine ever made this has really opened up the future of vaccines.
Because if the spike protein does mutate, it’s as “simple” as resequencing and replacing, and then the vaccine is ready to be made and tested again.
It may even get to a point (way down the road) where you don’t have to run all the trials again, but we have to get to a place where we find out what changes don’t affect humans, and what do.
But with mRNA, it won’t ever be starting from scratch.
Does he say if we might be able to use this for flu vaccines in the not too distant future?
I know, it’s so cool!
I’ve never done large scale genetic stuff, but in grad school (forever ago) I did some work studying how adding or deleting genes from alphaviruses changed mammalian immune responses, so I’ve got a mid-level understanding of it. Enough to understand most of what the studies say, and to be excited about how the vaccine works overall 
Definitely not enough to make vaccine, though. Can you PCR an entire virus genome? How else do you make enough? I don’t even know!
Yes.
Moderna is already doing trials for two variants (not FDA trials, like internal. I don’t think they are ready for humans.)
But it would still be a different vaccine per strain (maybe not a different jab, but the genetic information would be per strain.)
Sadly, there is some factor of profitability. It costs a fortune to do all this. So if there isn’t demand for it, companies can’t/won’t do it.
But if it’s a virus…it has RNA…
I don’t think flu started with just one protein, I think it’s always had two. Each protein (H and N) can mutate the way the SARSCoV2 spike protein can, but they can also really easily swap out one variation of H (or N) for another. So H1 is mutating slowly over time, but also H1N1 can become H5N1 very quickly.
(Hopefully that was both accurate and legible).
Soooo I told the nanny we were happy to pay her grocery delivery fees for a service of her choice given the extra risk for groceries. And she said she tries to be very safe, but will keep that in mind.
Awwwwkward… If I was her I’d take me up on the offer and call me a great employer but I am worried she thinks I’m super controlling.
I will admit, the hassle of ordering groceries online does drive me rather batty. Somehow my mind doesn’t register that there are 27 varieties of strawberry yogurt when I’m in the store, but scrolling through it freaks me out and makes me second guess every choice.
I don’t trust order pickers to get me good produce. I want my bananas green but not too green and my avocadoes two days away from ready and my tomatoes properly red but not soft.
He said, yes, you could PCR an entire virus genome, you’d have to do sections, but most are pretty small…like 4000-10,000 base pairs.
(The virus that causes covid 19 has around 30,000 base pairs, doesn’t take long to sequence)
Just to add some words since I did a whole presentation on this last spring–influenza is really weird in that it holds its RNA in multiple different chunks. So there’s the slower change that comes with mutation (called antigenic drift) and a faster change that happens when different influenza viruses trade some chunks (called antigenic shift). Which is how they come up with combinations of Hs and Ns that could be potentially scary.
Evading the annual vaccine comes because there are just a lot of different kinds that could become more prominent and because they “drift” over time. When we get really concerned is by the possibility of something that circulates easily but is relatively less harmful in animals and circulates poorly but is more harmful in humans may become something that is harmful in humans AND circulates well in them due to “shift”
Coronaviruses don’t have the chunks of RNA, so they are more limited to the “drift”.
I leave hilariously high-maintenance notes on the produce items I order. The best one ended with “sorry my kids are very picky” (they are - I try to avoid too many scenarios where I am stuck eating all of one produce type because it wasn’t nice enough so no one else will eat it). It’s also infuriating to receive produce that goes bad a day or two after receipt.
I do grocery pickup at walmart because you have to approve all substitutes.
But the grocery store near me just has a “allow substitutes” and they will do things like paper towels instead of toilet paper, or white sandwich bread instead of gluten free pita. WTF?