Statement from the UK Joint Committee on Vaccination & Immunisation (JCVI) on why they believe their strategy will achieve maximum impact:… 1/n
...They point out that most of the people who got sick with Covid-19 between 1st & 2nd doses of Tozinameran (BNT/Pfizer vax) did so in the 1st 2 weeks, so the efficacy after 2 weeks was 89% (95% CI 52-97%). But Pfizer stresses... 2/n
...that's only known for people who got their booster shot at 3 weeks, so it's unknown if it stays high for up to 3 months… For the Oxford/AstraZeneca vax, they rely on a subgroup analysis - but the data isn't provided...3/n
...JCVI says you can generally expect better immune response to a booster when it comes a bit later. That can't address immunity in the interval in the absence of trials designed to test this theory. They're recommending this because of short-term lack of vaccine doses...4/5
...Best case: they're right; enough 1st doses arrive to get enough people vaccinated; added benefit outweighs loss of protection from Pfizer proven regimen; enough 2nd doses arrive within 12 weeks. A lot seems to hinge on confidence that AstraZeneca can deliver enough in time 5/5

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More from @hildabast

30 Dec 20
#tbt This is the amazing Anna Wessels Williams (1863-1954) in the early 1900s. Her sister nearly died in childbirth in 1887: distressed by her treatment, she entered medical school. She moved to lab work in 1894: her 1st major breakthrough came fast ...1/4…
...While her boss was on vacation, she solved the barrier to high-yield diphtheria vaccines. She followed that with a 2-year sabbatical at the Pasteur Institute, creating a rabies vaccine that would be mass-produced in the US. Next was a rabies test in 1905 used for decades...2/4
...She was on the frontlines of the 1918 influenza pandemic, developed a more accurate diagnostic test for trachoma, & co-published a major textbook as well as one of the early successful science books for the public in 1937 ... 3/4
Read 4 tweets
29 Dec 20
Well, dear readers, my take on "the winning formula" for Oxford/AstraZeneca did not age well. According to the Indian manufacturing partner, it isn't the "low"-dose-1st subgroup. It's another subgroup, perhaps a subgroup of a subgroup...… HT @wogboy11 ..1/6
..The sweet spot he says is "a 2-to-3 months’ gap between dose 1 & dose 2". First let's recap their original data. They said intervals didn't make a difference. For the "standard"-"standard" group >8 wks apart vaccine efficacy was 65·6% (24·5 to 84·4). Ditto 6 weeks cutoff ..2/6
...The protocol doesn't limit the possible exploratory subgroup analyses ⬇️: so many ways they could have found a subgroup that hit this mark. Eg half the already-small "low"-dose-1st group had >12 wks apart: sliced off those perhaps? But I don't think that's the main point ..3/6
Read 6 tweets
28 Dec 20
MHRA verdict reportedly coming any day for the Oxford/AstraZeneca vaccine. I've been asked if I think their process is comparable to FDA's. Good question, post-Brexit. So I looked at 3 regulator reports for Tozinameran (BNT/Pfizer): FDA, MHRA, EMA (Europe) ...1/6
...2 agencies have unequivocal advantages:

1) Only the EMA did manufacturing inspections, which is a very big deal;

2) FDA had greater transparency: they're the only 1 releasing manufacturer briefing, released reports pre-committee, live-streamed committee discussion ...2/6
... FDA assessment report: 92 pages, almost all clinical data/issues, extensive data analysis - released days before their decision;

MHRA: 51 pages, not as much analysis - released 2 weeks after decision;

EMA: 140 pages, extensive data analysis, wide coverage ...3/6
Read 7 tweets
27 Dec 20
The AstraZeneca boss says they have new data for "the winning formula" that shows as good a result as Tozinameran (BNT/Pfizer) & Moderna. Based on what we know so far, is that likely? Well, yes...and no... 1/6…
...Protocol for their pooled analysis of trials had 2 analyses, dependent on reaching set events (people sick with Covid-19 more than 2 weeks after 2nd dose) in the standard-standard dose group: 53 events for the 1st analysis, 105 for the "final"... 2/6…
..We've seen 1st analysis: 98 events in that group. So they only needed a few more events to get to final of 105. Vaccine efficacy in that group was 62·1% (95% CI 41·0–75·7): with upper bound 75.7%, small data increase unlikely to get them over 90% ...3/6…
Read 7 tweets
15 Dec 20
Moderna data has arrived at the FDA.... I'll be tweeting about the 54-page document by the FDA… The brief from Moderna is much smaller than BNT/Pfizer's - only 84 pages (+ a 7-page presentation)… 1/n…
..Efficacy data is for 27,817 people randomized to either vaccine or placebo; & there's safety data for 30,350 people. I'll get started with the adverse events data, because that has been a question mark for this vaccine...2/n
...The FDA raises lymphadenopathy & Bell's palsy again. More people with lymphadenopathy with Moderna's vaccine than BNT/Pfizer's: 173 in vaccine group, 95 in placebo. Bell's palsy similar. Frequency of serious adverse events (SAEs) low: 1.0% in vaccine & placebo arms...3/n
Read 17 tweets
10 Dec 20
#tbt This is the dedication, with Eleanor Roosevelt, for the Polio Hall of Fame, honoring 17 scientists critical to polio research & the vaccine. The only woman scientist is in the center. She's Isabel Morgan (1911-1996) ... 1/5…
...Morgan cracked 2 major barriers that made the Salk vaccine possible: identified 3 serotypes for polio that needed to be protected against. Then in preclinical studies, she showed inactivated vaccine could work if you added adjuvant & a booster shot ...2/5
...These are her parents, both geneticists. She's Lilian Vaughan Morgan, a pioneer in using Drosophila as a model, revealing some of its chromosomes…

He's Thomas Hunt Morgan, 1933 Nobel prize winner for chromosome discoveries… ...3/5
Read 5 tweets

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