Eric Feigl-Ding (@DrEricDing): ⚠️TWO DIFFERENT #COVID19 PANDEMICS—Many think with cases dropping that pandemic is nearly over. But truth is, there are now 2 different #SARSCoV2 pandemics diverging—old strain is waning, while the more contagious #B117 strain is dominating. We will be soon slammed very hard. 🧵
https://twitter.com/DrEricDing/status/1357566949404905472/photo/1
Eric Feigl-Ding (@DrEricDing): 2) Here is what is really going to happen... most countries are having a gentle case decline with R(e) currently around 0.9. But this is deceiving. The #B117 is still relatively rare so far, so the R is being influenced mostly by the old common variant. But not for long...
https://twitter.com/DrEricDing/status/1357567789544914945/photo/1
Eric Feigl-Ding (@DrEricDing): 3) Here is what is going to happen... currently R is ~0.9 in many places, but with the more infectious #B117, the R will jump 50% approximately. And it is inevitable (all CDC and Danish models say this) that B117 will take over as the reigning dominant variant soon...
https://twitter.com/DrEricDing/status/1357568274012192775/photo/1
Eric Feigl-Ding (@DrEricDing): 4) and when that happens, what worked before to keep the pandemic contained at R of 0.9 will no longer work. Here is the model for Alberta, 🇨🇦 by @GosiaGasperoPhD. The B117 dotted red line will soon dominate and drive a new surge in latter half of March and April.
https://twitter.com/DrEricDing/status/1357568936942968832/photo/1
Eric Feigl-Ding (@DrEricDing): 5) And Denmark 🇩🇰 CDC has found the same thing. I GQR works now for keeping R around 0.9 or even 0.8, will absolutely not work anymore once #B117 variant takes over. Forget about it. We will be hit hard. But there is a way—if we suppress R to 0.7 or less.
https://twitter.com/DrEricDing/status/1357569436404903936/photo/1
Eric Feigl-Ding (@DrEricDing): 6) The solution to defeating the #B117 is to chase a #ZeroCovid approach and slam the R even lower to below 0.7.... but optimally 0.6 or less. So that even when the #B117 arises, it will keep R under 1 (0.6*1.5=0.9). And by keeping R at 0.6 now—we will have buffer room for B117.
https://twitter.com/DrEricDing/status/1357570672860495872/photo/1
Eric Feigl-Ding (@DrEricDing): 7) And again Denmark 🇩🇰 CDC agrees with that assessment. Their model for R of 0.8 shows it is insufficient to defeat #B117. But its model for R 0.7 shows it can be enough.
https://twitter.com/DrEricDing/status/1357571184825622528/photo/1
Eric Feigl-Ding (@DrEricDing): 8) The problem is that of the declining states, only 1 state is under R 0.7... which is Wyoming (figure below sorted from lowest to highest R). Every other state’s R is over 0.7. Thus while they would yield decreases now—they won’t once #B117 takes over.
https://epiforecasts.io/covid/posts/national/united-states/
https://twitter.com/DrEricDing/status/1357571975816896512/photo/1
Eric Feigl-Ding (@DrEricDing): 9) Meanwhile, the replacement thing is happening in England. #B117 is dominating while old common #SARSCoV2 is all but nearly gone. Total cases dropping only because of tight UK lockdown. But can UK sustain & not let up on gas pedal before politics caves to reopen too soon?
https://twitter.com/DrEricDing/status/1357573654578659332/photo/1
Eric Feigl-Ding (@DrEricDing): 10) Here is another @GosiaGasperoPhD model of the same thing. Keeping the R at 0.8 level is not enough to stop the spread once #B117 takes over.
https://twitter.com/DrEricDing/status/1357574222281904128/photo/1
Eric Feigl-Ding (@DrEricDing): 11) Denmark 🇩🇰 CDC @SSI_dk has been warning about this for over a month. The world hasn’t been listening. Aggressive mitigation for keeping R under 0.7 now is the only way.
⚠️CRUSH VIRUS NOW OR ELSE WE ARE SCREWED: Denmark’s CDC thinks new B117 #SARSCoV2 variant is so much more contagious (R +0.4 to +0.7) & inevitable that **if any country does not crush the R<0.7 now**, we will be completely #COVID19 screwed by Feb/March.🧵
— Eric Feigl-Ding (@DrEricDing) January 6, 2021
https://t.co/CG1iZNx6uI pic.twitter.com/W7v1iAsgw3
Eric Feigl-Ding (@DrEricDing): 12) Let’s slam this home. suppose we have 1000 cases/day now... with an R=0.86 we could reduce it to 500/day in 2 weeks.
➡️But w/ added contagiousness of B117 variant that has ~60% higher R, in 2 weeks, 3000 new cases/day instead.
➡️6x difference in 2 wks
HT @GosiaGasperoPhD
https://twitter.com/DrEricDing/status/1357575429121540103/photo/1
Eric Feigl-Ding (@DrEricDing): 13) The problem is that to get R low enough, what used to work won’t work anymore. When we previously could afford to open schools, it may be that when B117 becomes dominant, we might lose that buffer to keep R<0.7.
7) Now how does the new B117 variant change public health measures? What used to work for Australia and Canada will no longer work anymore. Only aggressive New Zealand and Austria 1st wave restrictions would now be able to stop the more transmissible B117 strain. pic.twitter.com/S2FKXF8g1n
— Eric Feigl-Ding (@DrEricDing) January 6, 2021
Eric Feigl-Ding (@DrEricDing): 14) Denmark CDC is becoming more right — contagious #B117 variant is continuing to solidify itself as 12.1% of sequenced #SARSCoV2 samples. 70% increase per week!

2.4%

4.0%

7.4%

12.1%
https://twitter.com/DrEricDing/status/1357578023910969346/photo/1
Eric Feigl-Ding (@DrEricDing): 15) Denmark officials, despite their lockdown induced case drop, are really panicking. Seriously— read the WaPo article or this thread 🧵 below. They express that without the 100% sequencing, they would have been lulled into complacency.
Denmark🇩🇰 even more worried than ever about new #B117 variant—B117 cases increasing 70% a week **despite strict lockdown**, says Denmark’s CDC genome sequencing *every single case in the country* for mutation. By contrast, 🇺🇸 sequencing 0.3%. #COVID19 🧵https://t.co/SPTy0cDkEH pic.twitter.com/8fCCyPwxPW
— Eric Feigl-Ding (@DrEricDing) January 24, 2021
Eric Feigl-Ding (@DrEricDing): 16) “Without this variant, we would be in really good shape,” said Camilla Holten Moller, co-leader of the @SSI_dk group modeling the spread of the virus.
“If you just look at the reproduction number, you just wouldn’t see that it was in growth underneath at all,”
https://twitter.com/DrEricDing/status/1357580010903777282/photo/1
Eric Feigl-Ding (@DrEricDing): 17) The good news so far is that all the vaccines tested so far perform decently against the main #B117 variants, but maybe less so against the 🇿🇦 #B1352 and 🇧🇷#P1 variants. Pfizer, Moderna, etc mostly good for B117. See thread 🧵 below to catch up.
BREAKING—Good & bad news—The Moderna #COVID19 vaccine fully protected against the UK 🇬🇧 #B117 variant... but was 6x less efficient at neutralizing the South African #B1351 variant in lab test. Moderna is testing a newly synthesized booster for it—3rd shot. https://t.co/4s4Ysr5cSp pic.twitter.com/CrCTrgNsre
— Eric Feigl-Ding (@DrEricDing) January 25, 2021
Eric Feigl-Ding (@DrEricDing): 18) So here comes the “but”... there is a new subtype of #B117 emerging... a mutated sublineage of regular main #B117 that had acquired the troublesome E484K mutation. This is the bad mutation that 🇿🇦 CDC & other studies helps B1351 evade antibodies.
NOT GOOD—so it seems 🇬🇧 government researchers have discovered that the already more contagious #B117 has further acquired the other troublesome E484K mutation seen in 🇿🇦#B1351 & 🇧🇷#P1 variants—in 11 patients. E484k is blamed for partial vaccine-evasion.🧵https://t.co/VwjT1WxVL8 pic.twitter.com/HAOahtFqcN
— Eric Feigl-Ding (@DrEricDing) February 1, 2021
Eric Feigl-Ding (@DrEricDing): 19) So what do we know about the #B117+E484K combo sublineage? Not much except this preprint study showing it is might be more resistant to antibody neutralization (more antibodies needed in lab study to neutralize the pseudovirus) than the common strain and the regular B117.
https://twitter.com/DrEricDing/status/1357584403166289920/photo/1
Eric Feigl-Ding (@DrEricDing): 20) This #B117+E484K isn’t for sure resistant to vaccine. We don’t know yet. And we don’t know if it will still be more contagious like the main B117 is, but we should assume it is—& take precautions that it might be the double combo of more contagious & maybe antibody resistant.
Eric Feigl-Ding (@DrEricDing): 21) could #B117+E484K be a fluke? Maybe. But it emerged recently in UK twice—independently arising in Wales, and arising in England. Just like in 🇧🇷 and 🇿🇦—so 4 times means convergent evolution is real. And convergent evolution is usually always greater survival fitness.
https://twitter.com/DrEricDing/status/1357586099061862401/photo/1
Eric Feigl-Ding (@DrEricDing): 22) The other way to win is with mass vaccination like in Israel 🇮🇱 that has already vaccinated 50 shot per 100 people in the elderly. Hence now look how fast the cases, hospitalizations are diverging for those age 60+ vs 59 or under. That is the effect of **mass** vaccinations.
https://twitter.com/DrEricDing/status/1357592764070981632/photo/1
Eric Feigl-Ding (@DrEricDing): 23) Actually, Israel 🇮🇱 has now reached 60 vaccination shots per 100 people: 4x UK 🇬🇧 and 6x the 🇺🇸. Rest of EU is much much lower.
https://twitter.com/DrEricDing/status/1357595943634403328/photo/1
Eric Feigl-Ding (@DrEricDing): 24) Another alarming datapoint: 10% of the village of Corzano 🇮🇹 has the #B117 variant—10% of all residents!!!
https://tg24.sky.it/milano/2021/02/03/variante-covid-corzano-brescia/amp?__twitter_impression=true
Eric Feigl-Ding (@DrEricDing): 25) Moreover, of the 10% of the infected 🇮🇹 village with #B117 UK variant, 60% of cases are kids from kindergarten and primary school, while other 40% are their parents. Schools in the village have closed now.
Holy cow: 10% of the village of Corzano 🇮🇹 has the #B117 variant—10% of all residents! 60% of cases are kids from kindergarten and primary school, other 40% are their parents, says the mayor. Schools in the village now closed. https://t.co/LhfmnuPdUP pic.twitter.com/htN5s0dbCU
— Eric Feigl-Ding (@DrEricDing) February 5, 2021
Eric Feigl-Ding (@DrEricDing): 26) BOTTOMLINE: unless we can mass vaccinate quickly like Israel (which is still not 1/3 of the way done), we must continue to mitigate with *premium* masks preferably and with airborne virus precautions to ventilate.
💡No virus = No mutation.
#ZeroCovid #COVID19 #COVIDzero
https://twitter.com/DrEricDing/status/1357603464797425664/photo/1
Eric Feigl-Ding (@DrEricDing): 27) here is where you can find the R(e) or R(t) in your US state.
https://epiforecasts.io/covid/posts/national/united-states/
Eric Feigl-Ding (@DrEricDing): 28) Please switch to premium masks if you can. KN95, KF94, FFP2, etc.... the new variant is just too contagious not to take extra precautions.
SWITCH TO PREMIUM MASKS—I’ve been saying it for months. We need to switch to KN95, KF94, or European FFP2 masks ASAP. The new #b117 #COVID19 is just too contagious. Cloth isn’t enough anymore folks. Germany 🇩🇪 & Austria 🇦🇹 mandating on all public transits. https://t.co/MfZhK4Uacg pic.twitter.com/iKQB4yNQrA
— Eric Feigl-Ding (@DrEricDing) January 24, 2021
Eric Feigl-Ding (@DrEricDing): 29) If you’re skeptical, you don’t have to take my word alone. Read this article in Science magazine by @kakape, he essentially outlines the same thing as I have with the ominous pandemic future of #B117. I trust my colleagues at Denmark 🇩🇰 @SSI_dk a lot.
Eric Feigl-Ding (@DrEricDing): 30) Also why aren’t we aware of that much #B117 in other countries besides Denmark and UK? Well because most countries sequence almost nothing (panel B is a log scale - so the drop off is much much worse as you go down), and also very slow in sequencing even when they do.
https://twitter.com/DrEricDing/status/1357656463242653698/photo/1
Eric Feigl-Ding (@DrEricDing): 31) Based on the limited #SARSCoV2 genomic sequencing that we do have... here is how different mutations are growing in each country so far (data slightly older by 1.5 weeks). Pink is the N501 mutation (seen in a few, but #B117 is the main variant with it)
https://covariants.org/per-country https://twitter.com/DrEricDing/status/1357671509603540996/photo/1
Eric Feigl-Ding (@DrEricDing): 32) Is #B117 a VARIANT or new STRAIN? People are now use them interchangeably. Let’s end the confusion. Experts say a variant is crowned a new strain when:
📌Becomes dominant (B117 🇬🇧)
📌More transmissible (B117), deadlier, or modifies immunity. #COVID19
https://twitter.com/DrEricDing/status/1357690382772031492/photo/1