Thread by @DrEricDing

WANING—After 3 doses, effectiveness of Pfizer vaccine against Omicron (BA1) hospital admission was 📌85% at <3 months but fell to 📌55% at 3-5 months. For ER admission, VE of 3 doses was 📌77% at <3 months but fell to 📌53% at 3-5 months. 2 doses worse. 🧵
thelancet.com/journals/lanre…

2) Trends in waning against SARS-CoV-2 outcomes due to the delta variant were generally similar, but with higher effectiveness estimates at each timepoint than those seen for the (BA1) #omicron variant.

3) Analyses were done for 11,123 hospital or ED admissions at Kaiser… ➡️effectiveness of two doses against the omicron variant was 41% against hospital admission and 31% against emergency department admission at 9 months or longer after the second dose. 👀

4) we have long known 2 shots has very poor efficacy against #Omicron. It was low ever since it emerged. Booster is still very very very important for protection with 70% efficacy against symptomatic infection early on.

5) there’s advantages to mixing vaccine types for boosters. See older thread 🧵 below.

6) and it seems the Moderna booster is very different than the Pfizer booster. The T cell response seems different too. Many experts advise mixing up the vaccines for broader immunity coverage.

7) And what is the efficacy protection against #Omicron mortality with 2 shots? It’s now only 59%! But with a 3rd shot booster— surges to 95%! You don’t want to stay at 59% protection. You want 95% with a booster folks! Please I beg you all. #getboosted

8) And again, data from 🇬🇧 shows, have had a full Moderna 2 shot series is much stronger than 2 shots of Pfizer or AstraZeneca. The data shows it’s over and over again. It’s the vaccine that has the least relative waning against #Omicron.

9) Here is an example of misinfo/ misunderstanding about vaccine efficacy / effectiveness. this is claim of 50/50 chance is a grave misreading. 55% vaccine effectiveness means it cuts risk by 55. So if instead of 2 in 100 with severe disease, it is lowered by half to ~ 1 in 100.

10) in case I’m not clear— the Moderna vaccine seems much stronger than the Pfizer vaccine. Even if the Booster for Moderna is just 50 mcg instead of Pfizer’s 30 mcg, it’s still likely stronger. Also the upcoming age <5 Moderna vaccine will be 25 mcg vs just 3 mcg for Pfizer.