Thread by @kakape

What do we know about the new #SARSCoV2 variants? How worried should we be? What does it mean?
I promised to summarize the main points from my reporting over the last few days.
So here is my latest story and a thread (and then it’s Christmas)
sciencemag.org/news/2020/12/u…

First: I’ve said “We don’t know yet” a lot over the last few days and we still don’t know most of what we want to know about these variants. Getting good answers takes times. Science takes time. But we are learning a lot fast and we know a lot more today than three days ago.

The UK variant:
I explained how B.1.1.7 caught scientists’ attention in my first story on this and why they were worried (sciencemag.org/news/2020/12/m…).
That worry has only increased. There is now more data available and it points to this variant really being more transmissible.

Initially skeptical scientists like @c_drosten have become more convinced. As @mugecevik told me: “We can’t really rule out the possibility that seasonality and human behavior explain some of the increase. But it certainly seems like there is something to do with this variant.”

@c_drosten @mugecevik This is about transmissibility. For now there is little to suggest it causes more severe disease or evades immunity. Scientists I spoke to can see a variant like this shaving a few points off efficacy of a vaccine but not dramatically reducing it. Experiments will tell us soon.

@c_drosten @mugecevik As @profshanecrotty pointed out the body makes a broad response to #SARSCoV2 and even just the spike protein. “It would be a real challenge for a virus to escape from that.” Measles and polio vaccines still work and are "historical examples suggesting not to freak out.”

@c_drosten @mugecevik @profshanecrotty Increased transmissibility is still really bad news. It’s not clear how much more transmissible the variant really is. But the numbers that modellers have come up with are worrying. Our job to keep the numbers down until people are vaccinated has likely become a fair bit harder.

@c_drosten @mugecevik @profshanecrotty How does the increase in transmission come about? We don’t know. There are several hypotheses: the variant might infect children better than previous variants. It might transmit faster. @BillHanage has a great thread on a preprint looking at this.

https://twitter.com/billhanage/status/1341857733633581063?s=21

@c_drosten @mugecevik @profshanecrotty @BillHanage The South African variant: We know less about 501Y.V2. This variant too seems to be spreading faster and there is anecdotal (meaning very weak) evidence of more severe disease in younger, healthy people. @JeremyFarrar told me he was at least as concerned about this variant. Why?

@c_drosten @mugecevik @profshanecrotty @BillHanage @JeremyFarrar 1. It has 3 mutations in the RBD, an important part of the spike protein. All seem a bit worrying by themselves and we don’t know what the combination means.
@JeremyFarrar: "These South African mutations I think are more worrying than the constellation of the British variant"

@c_drosten @mugecevik @profshanecrotty @BillHanage @JeremyFarrar 2. Africa has largely escaped the brunt of this pandemic. Many scientists think younger age and warmer climate together with other factors make #SARSCoV2 spread less efficiently there. Worry is that an increase in transmissibility could get over these factors.

@c_drosten @mugecevik @profshanecrotty @BillHanage @JeremyFarrar So, lastly, what does it mean that these variants popped up in the first place?
There are two important strands to that: How we discovered them and how they arose.

@c_drosten @mugecevik @profshanecrotty @BillHanage @JeremyFarrar Discovery: The UK has sequenced more #SARSCov2 viruses and done so faster than any other country. The story shows how important and helpful genomic surveillance can be and that we are affording ourselves an awful lot of blindspots in this pandemic.

@c_drosten @mugecevik @profshanecrotty @BillHanage @JeremyFarrar There are already indications that the last few days have prompted many countries to sequence more, release more data. So if there is a flurry of new variants/mutations announced in the next days and weeks that is partly because we are now looking more closely/sharing more.

@c_drosten @mugecevik @profshanecrotty @BillHanage @JeremyFarrar Origin: Most likely hypothesis for now is that these variants arose in patients whose immune system was weakened and who were infected over a long period of time. “It’s simply too many mutations to have accumulated under normal evolutionary circumstances”, @stgoldst told me.

@c_drosten @mugecevik @profshanecrotty @BillHanage @JeremyFarrar @stgoldst There are at least two reports of immunocompromised patients infected for more than 100 days showing that the virus accumulated some of the same mutations seen now in the variants in UK and South Africa.
nejm.org/doi/full/10.10…
medrxiv.org/content/10.110…

@c_drosten @mugecevik @profshanecrotty @BillHanage @JeremyFarrar @stgoldst It's possible that virus sequences in these patients are a window into the future, showing us what to expect from #SARSCoV2 evolution. @jbloom_lab has a fascinating paper showing something similar for flu: elifesciences.org/articles/26875

@c_drosten @mugecevik @profshanecrotty @BillHanage @JeremyFarrar @stgoldst @jbloom_lab There probably needs to be more debate about how best to care for such chronically infected, immunocompromised patients, what treatments make sense and how to make sure they don’t transmit onwards late in the infection. I also hope we get more research on virus evolution in them.

@c_drosten @mugecevik @profshanecrotty @BillHanage @JeremyFarrar @stgoldst @jbloom_lab But the biggest take-away from all this is what @mvankerkhove told me:
We need to keep number of infections low even as vaccinations start.
“The more of this virus circulates, the more opportunity it will have to change,” she said. “We’re playing a very dangerous game here.”

@c_drosten @mugecevik @profshanecrotty @BillHanage @JeremyFarrar @stgoldst @jbloom_lab @mvankerkhove So the two-sentence, sad summary:
The UK/SA variants show that we should be doing what we should have been doing all along, keeping the number of infections really, really low.
That job has become even more important now - and even harder.