Thread by @DrEricDing

⚠️OMICRON “EVADES” NEUTRALIZATION—1st ever #Omicron variant study of blood from Moderna, Oxford-AstraZeneca, Pfizer vaccinated, vs survivors of Alpha, Beta, Delta variants. Omicron #B11529 evasive—but 2x Pfizer/mixed stronger>> convalescent; 3x hit best.🧵 medrxiv.org/content/10.110…

2) “We found that sera from vaccinated individuals neutralized the B.1.1.529 variant to a much lesser extent than any other variant analyzed. Neutralization capacity against #Omicron was maintained best against sera of “infected + 2x vaccinated” or “2x vaccinated + infected”

3) it’s clear vaccine neutralization of #Omicron is much harder than any other variants tested - Alpha, Beta, or Delta. Though 2 doses of Pfizer or Pfizer+AstraZeneca mixed vaccination had somewhat better performance against #Omicron. But 2x AstraZeneca not good enough.

4) I’m kind of surprised that 2x doses of Pfizer showed stronger benefit than 2x doses of Moderna. Moderna is a >3 times the dose. But the author says it might be due to interval difference. Will want to see more duration data.

5) I think it’s clear we need boosters. But also maybe variant-adapted newly #Omicron-tailored vaccines in the near future.

6) This above Innsbruck neutralization study matches the drop in vaccine effectiveness seen in the UK — where 2x shots of Oxford-AstraZeneca has little benefit without a booster, and 2 shots of Pfizer slightly better but still only in the low to mid 30% VE without a booster.

7) So how bad is the VE data for 2 AZ doses? Well let’s walk through it… the table tells more about the efficacy against #Omicron beyond the figures above. 2 shots of Oxford-AstraZeneca don’t even have enough data for those <25 weeks. But for 25+ weeks, the 5.9% VE stood out.

8) Another study found that those infected with the original strain much sharper drop off in ability to neutralize #Omicron. ➡️Bottomline: DO NOT RELY ON PAST INFECTION TO PROTECT YOU from Omicron! Get vaccinated / boosted!

And follow my former mentor: @AliNouriPhD

9) Semi-good/bad news with 2 shots of Pfizer, the VE starts at 88% between 2-9 weeks after the 2nd shot. Good, but it quickly drops to 48.5% by weeks 10-14. Then drops to 31% by 15-19 weeks. Then it hovers at 36.6% at 20-24 weeks. Then 34.2% at 25+ weeks. But 75.5% w/ booster!👀

10) By now, i hope everyone understands how much worse #Omicron is in evading vaccines and past infection immunity —by leaps and bounds worse by old strain and worse than Delta. We need some radical realism, not delusional dismissive ness that Omicron won’t hit hard. Booster now!