Thread by @DrEricDing

⚠️Confirmed—#DeltaVariant is by far the *most contagious** variant found to date, with a transmissibility that is ~2x faster than older strain. #P1 is 2nd fastest, says @WHO study.🧵

📍#B117 #Alpha—29% faster

📍#B1351 #Beta—25%

📍#P1 #Gamma—38%

📍#B16172 #Delta—97% #COVID19

2) “Effective reproduction number of SARS-CoV-2 variants of concern/interest compared against each other, 64 countries, data until 3 June 2021”
eurosurveillance.org/content/10.280…

3) “Of the six variants currently designated as VOI, five were considered in our analysis and among these, only B.1.617.1 (#Kappa) and B.1.525 #Eta demonstrated a statistically significant increase in the effective reproduction number of 48% and 29%, respectively.”

4) To be clear, “faster” transmission of #DeltaVariant means “change in effective reproduction number of SARS-CoV-2 variants relative to non-variants” (from 64 countries through 3 June 2021).

➡️Thus if the original Wuhan 1.0 strain had an R0 of ~3.5, x2 for #Delta—to get 7. 👀

5) Notice how the “other” older strain (non-VOC/VOI) in dark green have all but disappeared from most countries. #B117 #alpha came to the scene during the winter, and #P1 #Gamma dominated Brazil and didn’t let #Alpha take hold.

But in UK, #DeltaVariant has overtaken alpha.

6) Also, the other India-origin varian #Kappa #B16171, while not officially a higher-risk-rated VOC, seems to be faster than the VOC’s #Alpha #Beta, and maybe #Gamma. I think #Kappa deserves to be upgraded. It’s found in outbreaks in Australia 🇦🇺 at the moment.

7) The new #DeltaVariant faster transmission data is why @WHO declared it a VOC 3 weeks ago in late May. UK 🇬🇧 declared Delta a VOC 2 weeks ago… but US CDC only declared Delta a VOC… 2 days ago.

8) With data of #DeltaVariant like this 2 weeks ago, it was quite obvious #B16172 was poised to be by far the fastest variant found to date.

9) Sorry, I’ve been super annoyed at the slow movement of the CDC to act and warn about the #DeltaVariant. They were relatively quite while rest of the world scrambled to contain the #B16172 variant from India— sometimes warning VOC status 3 weeks is just too late.

10) I’ve been fuming for a while—because CDC should have acted when it saw clear data on #DeltaVariant consistently soar like this across many states. We have lots precious time.

11) #DeltaVariant also is more confusing to identify - it mimics the common cold, and the classic #COVID19 symptom of loss of smell is much more rare! This is a huge change.

12) When I see #DeltaVariant stats like these… I get worried. Granted, many of the double vaccinated are more elderly in the UK, but that doesn’t bode well for elderly protection then.

13) Similar #DeltaVariant worries from a 🇨🇦 hospital— ➡️Outbreak even w/ 2 dose of mRNA vaccines—16 patients & 6 HCWS #DeltaVariant positive. 6/16 patients & 5/6 HCWs had received 2 doses of #COVID19 vaccine. A 2x vaccinated 80-year old also died. cbc.ca/amp/1.6063802

14) Here is a BEST EXPLAINER video on #DeltaVariant. Part 1 of 3.

➡️ 1 dose isn’t enough.

by @IndependentSage @VickiGSP.

15) again, @IndependentSage also emphasizes that people who are either elderly or have morbidity may be even more susceptible to #DeltaVariant - even if vaccinated.

Video part 2 of 3 by @VickiGSP

16) We don’t want lockdown type restrictions. So the way to avoid that is with faster actions.

17) the main problem with #DeltaVariant is that the 1 dose strategy isn’t good anymore. 1 dose vaccine efficacy is likely just ~33% or so with either AstraZeneca or Pfizer. That is trouble for millions that aren’t two dose vaccinated yet.

18) back to the age issue, notice how virus neutralization drops with age. Problem with #DeltaVariant (right) and vaccine is that among young adults, they start at lower vaccine neutralization level than even an elderly person with original strain!

19) Now the crisis—Let this sink in—over 100 US counties right now have <20% of local population vaccinated. That is a “time bomb waiting to happen” says Dr @mtosterholm.

This will not end well low vaccinations area of the US & around world. #COVID19

20) And now @WHO_Europe chief says #Delta is soon going to take over Europe as well. Most countries in Europe are not acting quickly or at all. This is Germany right now… #DeltaVariant (brown) is soaring. #P1 Gamma is tagging along and rising too.

21) MORE SEVERE—UK scientists found #DeltaVariant to have 2.4-2.6x higher risk of hospitalization than B117 #AlphaVariant. But Alpha is 64% higher risk than original for hospitalization. So 1.6*2.5= 4.1x. That’s why Delta likely has 4x higher hospitalization risk than original ⚠️

22) Bottomline: #DeltaVariant is the most contagious fastest spreading variant to date. It’s more severe, and while 2 dose efficacy is good, Delta has 1 dose vaccine evasion—that is the “problem” as Dr Fauci put it. And most folks aren’t 2 dose vaccinated.

23) Regarding J&J, I have no direct evidence-based position. However… it’s not technically a 2-dose vaccine. if you’re interested what some immunologists think… read thread 🧵 below… but the CDC needs to put out guidance on this soon. Very soon.

24) Damnit we should have acted faster against #DeltaVariant. Now the world is going to pay a heavy heavy price.

25) In case anyone had any doubt how utterly dominant #DeltaVariant is— it just hit 99% of all #COVID19 cases in the UK. The US is where UK was in late April / early May.

26) please sign the petition to CDC for urgent #DeltaVariant action. It is by @endCOVID19 & @CovidActionGrp and a “coalition of scientists, public health officials, epidemiologists, health care workers, educators, advocates, parents, & concerned citizens:
change.org/p/centers-for-…

27) folks— we seriously need to act, and act damn fast. #DeltaVariant is going to be a serious scourge for many countries around the world soon, not just for India and UK. US is on the tipping point… see thread 🧵 below.

28) Siri, define “#DeltaVariant is fast spreading”….

➡️ Delta variant can infect people in mere seconds via fleeting contact.

Siri, does this fleeting exposure infection happened often?

➡️ it happened twice in one outbreak. Video camera evidence included. See thread 🧵

29) we must also be vigilant about #DeltaVariant and school children. Kids can transmit very efficiently. And kids can get #LongCovid too - 1 in 12 in fact.