Federal health officials are tracking a new variant of COVID-19 that could possibly spread rapidly and not be stopped by current vaccines or people who’ve developed immunity to the virus.
But the variant could also simply go away.
Only a few cases of the new BA.2.86 variant have been found so far worldwide. The first in the U.S. was reported recently in Michigan’s Washtenaw County: an older person who became sick but was not hospitalized.
Professor Jesse Bloom studies COVID-19’s mutations. He says this particular COVID variant is unusual but the situation facing health officials is not.
The following interview has been edited for clarity.
Dr. Jesse Bloom: SARS-CoV-2 is continually evolving in humans. So there’s new variants showing up all the time. If you follow this closely, like I do, every week or two there’s another variant people are discussing. But what got the attention of me and a number of other scientists about this new variant — which is now being given the hard-to-remember name of BA.2.86 — is it has an extremely large number of mutations in its spike protein. Normally when new SARS-CoV-2 variants emerge, they may have a handful of mutations relative to the sequences that came before them, sort of their “parents.” But this BA.2.86 new variant has over 30 mutations in its spike protein, relative to its closest ancestor. So this represents a really big jump in the number of mutations and has the potential to reduce the ability of this variant to be recognized by antibodies, both those used as treatments and antibodies elicited by vaccination and infection. It’s still very rare and we don’t know whether it’s going to just fizzle out or spread widely. But, as scientists, we’re trying to track it carefully. We want to be as on top as much as possible about what could be the possible scenarios here.
Quinn Klinefelter, WDET News: I’d heard this new variant could perhaps be far more transmissible than some of the others that have been found recently, similar to when Omicron first spread so rapidly. Is that an exaggeration, in your view?
That’s something that’s not clear at this point. The virus certainly has a lot of mutations. It is an evolutionary jump similar to that which gave rise to the original Omicron. However, we don’t know if this variant will actually be able to spread widely or not, how transmissible it will be. Because having a lot of mutations is not a guarantee that a virus is actually going to be good at transferring to humans. Right now there’s a very small number of these BA.2.86 sequences that have been identified. However, these sequences have been identified in several countries, including one in the U.S. in Michigan, as well as in Denmark, Israel and the United Kingdom. So it indicates the variant’s transmitting at least to some degree. But whether it will really have the transmissibility to let it take off and spread widely, like the original Omicron did, or whether it will fizzle out is just something where there’s not sufficient data to know at this point. Either is a possible scenario.
When investigators are examining it, is there any way that they get a handle on whether or not it is likely to be more transmissible? Or do you just have to wait and see if a number of people catch it or if people don’t?
We basically just have to wait and see. Scientists such as myself can look at the sequence and estimate how much this virus will be able to escape from antibodies, which is going to be quite a bit because it has quite a few mutations in the spike protein. But we’re not able to estimate how transmissible a new viral variant is just from its sequence. The only way that we can accurately estimate that is just wait and see what happens each week. If there’s more sequences identified this week than the week before, then we know the variant is taking off. So I think in a few weeks we’ll be able to give a pretty good assessment. But right now it’s just too early to say. Those sequences are across multiple countries, so there had to be some cryptic transmission. That said, it’s still not possible to say whether this variant is actually going to be able to out-compete the other SARS-CoV-2 variants that are already out there and spreading. So the fact that it’s in multiple countries is why we should be watching it to see what happens. But it’s just too early to say at this point.
You said that it had evolved to the point where it was able to evade some antibodies because of the number of mutations that it has. Does that mean that the current vaccines and other immunities that could be built up in the populace might not be nearly as effective against this particular variant of COVID?
Yeah. One thing I should point out before people get too alarmed is that we know there’s some broad forms of immunity against SARS-CoV-2 that work fairly well even against fairly distant variants. So we’re in a much better place right now than we were in 2020 and 2021 because the vast majority of people in the world have either been vaccinated against SARS-CoV-2 or infected with it, or often both. That’s going to provide them some broad protection against any SARS-CoV-2 variant. However, when a virus has a lot of mutations in the spike protein like this, those antibodies are less effective, particularly less effective at blocking transmission. And so we do think, based on the number and location of these mutations in the spike protein, that the immunity elicited by recent infections and also the immunity elicited by current vaccines, as well as the booster that’s going to come out this fall, would probably work less well against this variant. But right now with this variant, there’s still only been a small number of sequences found globally. And there’s a lot of SARS-CoV-2 variants out there right now that are closely related to the strain that’s in the new vaccine that’s being rolled-out. So at this point, the new vaccine remains well matched to most of the SARS-CoV-2 that’s circulated in the world. But we do need to keep a careful watch on this new BA.2.86 variant. If it started to spread very widely, the new vaccine coming out this fall would not be as well matched to it.
What would lead such a variant to fizzle out? Does it just do it automatically if it can’t find enough hosts to jump from one to the other to the other? Is there any particular thing that will make it so that it doesn’t spread widely, if it has all these other factors that you’re mentioning?
That’s a really great question. The ability of a variant to spread in the population, now that most people have some form of immunity, is a combination of how well it can get away from the antibodies and other forms of immunity that people have. And this BA.2.86 variant is going to be quite good at that. It also depends on how good it is at transmitting independent of antibodies. And that’s what we’re really not sure of right now. We have seen other variants with a fair number of mutations sort of appear, be tracked for a while and then eventually just be sort of out-competed or fizzle out because they’re not transmissible enough. We haven’t seen one with quite this many mutations since Omicron. But certainly there have been many variants that have fizzled out. And there have also been some variants that have not fizzled out. And we’re just at the point right now where we don’t know where it’s going to fall for this BA.2.86 variant. That’s just the nature of trying to catch these things as early as possible. You catch them before you’re sure what the significance is going to be.