Thread by @HelenBranswell

1. The #ACIP meeting on #Covid boosters is about to begin. Day long meeting. It will be interesting to see if they try to put some guard rails up around a pick-your-own-adventure booster process that @US_FDA seems to have green lit.
I will try to live tweet, but no promises.

2. If you want to listen to the meeting, here's the link: video.ibm.com/channel/VWBXKB…

3. CDC Director Rochelle Walensky, who overruled #ACIP the last time the committee met on #Covid vaccines, is addressing the committee now. No mention of having overruled ACIP.

4. "Know that I am listening and looking forward to what you have to say." — CDC Director Rochelle Walensky to #ACIP.

5. This meeting is going to be grueling. So many presentations. Many, many slide sets and a lot of data. Agenda here: cdc.gov/vaccines/acip/… #ACIP

6. Part of the challenge for the booster shot rollout is that with the Moderna vaccine, there are 2 different boosters: a full dose — 3rd dose — for immunocompromised people given 1 month or longer after dose 2 and a 1/2 dose booster for other eligible people, given at 6 months.

7. Moderna is making the case for its booster. Showed this slide showing breakthrough cases over time in people in their Phase 3 trial. Big spike in July and Aug, after Delta emerged. #ACIP

8. In terms of side effects after the Moderna booster doses, in general they were not greater than reported side effects after the primary series, ie dose 1 & 2. Here is data on serious and medically attended side effects.

9. Important info just emerged in the Q&A on the Moderna booster. Booster doses won't be shipped in different vials; HCWs giving vaccinations will draw out a half dose. But the stoppers of vials can only be punctured 20 times. For 15 full dose vials, this could create wastage.

10. Now #ACIP is hearing a presentation from J&J about their booster. A lot on the line for J&J here today. ACIP has been very concerned about people who got the 1-dose J&J vaccine.

11. The Moderna and J&J presentations are very like (identical?) to the ones made by the companies at last week's VRBPAC meetings. So I'm not driving myself crazy trying to live tweet 'em.

12. J&J's Penny Heaton is making a pitch for homologous boosting for people who received the company's vaccine. ie: recommend that J&J recipients are boosted with J&J, please. #ACIP

13. #ACIP member Keipp Talbot asks a very smart question. J&J presented UK data from the use of the AstraZeneca vaccine to try to come up with an estimate of how frequent thrombotic events are after boosters with adenovirus-vectored vaccines (AZ & J&J are both Ad-vectored.)

14. Talbot noted that in the UK, after the thrombotic events came to light, they recommended young women (at highest risk) stop getting the AZ vaccine/not get boosted with AZ. So the UK data can't give a true picture of TTS after dose 2, Talbot said. Important catch. #ACIP

15. Robert Atmar, who until recently was on #ACIP, is presenting data from the NIH-funded mix-&-match #Covid vaccine trial. Atmar, from Baylor College of Medicine, was one of the PIs in the mix-&-match trial. "Today I'm only presenting antibody data." And only early responses.

16. Atmar is asked how many people in the mix-&-match study were older adults. Not many, he said, only between 1-3 per group in the 9 group study.
So potentially what this study tells us about heterologous boosting of #Covid vaccines comes with an asterisk for the elderly. #ACIP

17. #ACIP is already running over. The 15 minute break (aka lunch) is being shrunk to 10 minutes. Reconvenes at 12:16 pm ET for the public comment period. @doritmi is one of the commentors, I believe.

18. #ACIP often runs late but it starts promptly.
Public comment section of the meeting starts now.

19. Presentation on what's known about the safety and reactions to 3rd doses of #Covid vaccines. Reactions after a 3rd dose of Moderna are pretty similar to Dose 2.

20. @CDCgov's Tom Shimabukuro starts first of several presentions on risk of myocarditis and pericarditis after #Covid vaccination, as well as CDC work trying to assess if there are long-term impacts of these cases. #ACIP

21. This point has been made before, but boy, this rate of myocarditis in younger males (under 20 yo) after an mRNA vaccine is ... not small. #ACIP

22. To date there've been 47 confirmed reports of thrombosis with thrombocytopenia syndrome in the US after receipt of the J&J vaccine. 15.3M doses of J&J have been administered. Among these TTS cases, there have been 5 deaths, said @CDCgov's Tom Shimabukuro.

23. Shimabukuro says there's limited data to assess if there's a risk of getting an mRNA vaccine after the J&J vaccine, but no signals of safety problems so far. #ACIP

24. In a presentation of data from Kaiser Permanente Northern California, it looks like the risk of myocarditis/pericarditis is higher after the Moderna vaccine than after Pfizer. But these data would be based on the Moderna full dose, not the half-dose booster. #ACIP

25. It is unclear if the myocarditis risk with the half-dose Moderna booster will be the same or lower, says #ACIP member Keipp Talbot, who chairs a work group on Covid vaccine safety.

26. And it starts: Pablo Sanchez says he agrees J&J vaccine recipients need a 2nd dose of vax, but he's "very, very concerned" about the idea of giving a 2nd dose of the J&J.
Talbot agrees, saying the ability to give heterologous boosts is a big opportunity to sidestep risks.

27. Talbot says she's worried about boosting young women with J&J and young men with mRNA vaccines, given the risks of TTS and myocarditis, respectively. #ACIP

28. Very short break.
I gotta say, October has been Adcomm-arama, what with the various VRBPAC & ACIP meetings. And there's 1, maybe 2 more next week.
Hitting the limits of my ability to concentrate. Dunno how those folks do it.

29. #ACIP is hearing data on vaccine efficacy of the various vaccines.
@CDCgov's Jefferson Jones says of the J&J vaccine: "There is no consistent evidence of waning."
J&J's vaccine never reached the heights of the mRNA vaccines, but it appears to be holding steady.

30. The vaccine efficacy data are ... kinda overwhelming. Half a million numbers. General trend: some decline.
What I want to know — & I suspect no one can tell me — is will a booster, especially after a longer interval, help stabilize protection at high levels?

31. Here's the conclusion slide for the VE presentation.
Another thing I'd like to know: Will mRNA boosters lead to stabilized boosting? Or is mRNA protection inherently short-lived?
@florian_krammer? @TheBcellArtist? @EJohnWherry?

32. If you are a data nerd (no judgment here!) you can download the very data dense presentations that #ACIP has been hearing here. Scroll down to the Oct. 21 part of the meeting to see the Covid material. cdc.gov/vaccines/acip/…

33. People have already been getting boosters. Nearly 11M people in the US have received them already, @CDCgov's Kathleen Dooling says.

34. But nearly 100M other Americans are already eligible for boosters based on the current eligibility criteria.

35. Still haven't heard a single reference to the fact that the US is talking about boosting tens of millions of people who are fully vaccinated at a time when only 2 out of 5 health care workers around the world have received a single dose of vaccine.
Not. One. Word.

36. Trite observation: People really have a hard time saying heterologous and homologous.

37. Gotta admit: this really confuses me. Even though everyone seems headed towards a booster and even though experts talk a lot about the mRNA vaccines needing 3 doses & the J&J needing 2, the definition of "fully vaccinated" isn't changing.
Even for the J&J?

38. So the way FDA-CDC are going to try to steer choice of boosters is coming into view. The EUAs the FDA issued made it look like we all get to choose whatever we want.
But @CDCgov's clinical considerations suggest people should get boosted with the same brand. ie don't mix.

39. Not sure how this will play out at the point of booster administration. Will pharmacists agree to let an individual choose? #ACIP

40. Keipp Talbot ask if it's possible to drop the suggestion that where possible people should get the same vaccine.
@CDCgov's Amanda Cohn says under the EUA, #ACIP cannot express a preference for heterologous boosting, but they permit it.

41. Talbot also said she thinks the J&J vaccine should be a 2-dose vaccine. @US_FDA's Doran Fink says the J&J is a 1 dose vaccine "at this time" but added that "this is not determinative" of what the vaccine may eventually be when more data are gathered.
Interesting.

42. In response to a question, Fink said people who are immunocompromised can get a 4th dose of vaccine 6 months after their 3rd dose. But that won't come into play for awhile because the 3rd dose for severely immunocompromised people was only approved in August.

43. Sarah Long asks tough questions. She tells the committee it claims to make evidence-based decisions when "what evidence do we have" that people under 50 need to be boosted at this point? (She excluded people who got the single dose J&J.) "I can't say that I am comfortable."

44. Long doesn't think some of the people who are currently eligible for boosters should be. But when #ACIP voted to exclude 1 group at the meeting about the Pfizer booster, CDC director Walensky overruled ACIP & included them. Good reason to believe Walensky would do so again.

45. Here's the first voting question #ACIP is being asked to vote on; this is for the Moderna booster, but worded to capture mRNA vaccines as a class.

46. Here's the voting question for people who got the J&J vaccine. Permissive of any booster brand.

47. Interesting to hear some #ACIP members openly admit they're likely going to vote to recommend boosters for people they don't actually think need to be boosted yet.

48. Keipp Talbot makes another attempt to make clear some people should really steer clear of particular vaccines. She asks if the language of the voting question on boosting for J&J recipients should state that young women should not get the J&J as their booster.

49. Talbot's suggestion doesn't seem like it's going to fly. CDC staff said this type of detail will be included in CDC clinical guidance, ie information for physicians and for individuals that will come out after these votes. #ACIP

50. Sounds like we're getting close to votes!
Hallelujah!

51. Beth Bell urges the committee to try to keep things clear and as simple as possible, and allow for flexibility. Because there's a real risk of totally confusing the public.
#ACIP

52. And the thing no one is saying out loud remains true. The CDC director overruled #ACIP when it tried to narrow who could get boosters last time it met on boosters. No reason to expect a different outcome this time.

53. Vote number 1, on the mRNA boosters, passes unanimously. 15-0

54. Vote number 2, on the J&J booster, passes unanimously. 15-0.

54. #ACIP meeting adjourned.