Thread by @DrEricDing

NEW VARIANT—New California variant CAL20C has recently found in over **half** of all samples in Los Angeles #COVID19 cases, & ~20-30% across CA. “I’m decently confident that this is a more infectious strain of the virus”, says expert from Cedar-Sinai. 🧵
nytimes.com/live/2021/01/1…

2) Dr. Charles Chiu, a virologist at UCSF said “It just popped up under our noses, and now it’s rising in multiple counties,” he said. “On the whole, it’s safe to say it’s going to spread outside of California.”

3) “Researchers are also looking in other states for CAL.20C, Dr. Plummer said, and have so far found it in Arizona, Connecticut, Maryland, New Mexico, Nevada, New York, Texas, Utah, Washington, Wyoming, & DC. It’s not clear yet how common it is outside California.”

4) CDC is working with California to learn more about new variant. “Currently, it’s not known whether this variant is any different from other SARS-CoV-2 viruses, whether those differences may have contributed to its emergence, or whether this emergence was merely a random event”

5) “Outside scientists are concerned about the findings, but say it’s still unclear whether the California variant’s mutations are giving it an edge — or whether it’s showing up so much just by chance.

6) “There might be a bias in the samples that scientists are looking at, for example. It’s also possible that CAL.C20 happened to become more common thanks to some big super-spreader events.

7) Dr. Chiu and his colleagues are now growing the variant in cells to see how quickly they multiply compared with other variants. The researchers are also going to observe how well antibodies produced by vaccines work against CAL.C20.

8) This CAL20C variant was first reported in early Jan. That mutant, which belongs to a lineage known as CAL.20C, seemed to have popped up in July but lay low till November. Then it began to quickly spread.

nytimes.com/2021/01/19/hea…

9) “I’ll say this particular variant is one to watch,” said @K_G_Andersen, who discovered one of the first samples of B.1.1.7 in the US. But he cautioned that it’s still unclear whether CAL.20C is getting more common because it has some biological advantage, or just by chance.

10) If #B117 & #CAL20C are both more contagious than other variants, it’s not clear how competition between the two of them will sort out. “CAL.20C has a big head start,” Dr. Vail said. “Even if B.1.1.7 is more infective overall, we may never see a big surge from it here in L.A.”

11) This is coming all the while CA has had a “jumbled” vaccine rollout.

“Our ability to expand and speed vaccine distribution depends on vaccine supply made available to CA. At the current rate, we’re looking at vaccine distribution that is much slower”
nytimes.com/live/2021/01/1…

13) It seems the new #CAL20C variant is growing pretty quickly in Southern California. medrxiv.org/content/10.110…

14) Nomenclature: Cal20C variant is also called lineage B.1.429, #B1429, which contains mutation L452R.

According to a Nature paper, L452R is one mutation that yielded at least 4-fold decrease in sensitivity to neutralizing antibodies. something to watch.
nature.com/articles/s4139…

15) Crazy thing is that the infamous E484K mutation that is evading immunity and vaccines partly in the #B1351 and #P1 variants isn’t even listed in this older paper of bad mutations from last year!! Clearly we have much to learn and there’s many more bad/good mutations.

16) Dug deeper... it seems mutation at the 452 amino acid position on the spike protein is one of the moderate immunity escape sites according to this study from @jbloom_lab. It’s not as bad to the 484 mutation site, home of infamous E484K, but still real.
biorxiv.org/content/biorxi…

17) Moreover, they also noticed that over time, the L452 mutation’s antibody escape potential increased over time in one subject F (see panel C bottom). Again, not the worst, but we need to test this again vaccinated people’s blood to know for sure.

biorxiv.org/content/biorxi…

18) Meanwhile, the other major worry is the rapid rise of the #B117 variant across the US, including California. But especially in Florida. It will dominate the US by mid to late March. Read 🧵

https://twitter.com/DrEricDing/status/1358468446548357123

19) the solution is strive and fight for a #ZeroCovid strategy. Elimination not just mitigation.

20) Potential future surge. But there is no fate but what we make. We can stem the growing underbelly of #B117 and other contagious variants if we act fast.

https://twitter.com/drericding/status/1359871587126763521