This issue is, appropriately, contentious. As a vaccinologist - & citizen & relative of people in at-risk groups - I fully support the UK decision to increase dose intervals of both our Ox/AZ product and the Pfizer product. I'd happily receive either with a >8w gap. Here's why 🧵

For the Ox/AZ vaccine, it's fairly simple. The trial demonstrated efficacy at a range of dose intervals. Antibody responses after the boost were significantly stronger with longer intervals - see table 3.
https://t.co/10KPvahJ64
(so in response to @drmarkporter's point, higher immune responses with a longer interval is proven & now public. I haven't seen a similar analysis for efficacy against disease but the data exists and I suspect the regulators & JCVI committee have)
For Pfizer, there isn't direct evidence of efficacy with a >3wk interval. But as widely publicised, efficacy in the period from 14 days after first dose to 21 days is high.
Can we extrapolate from this to a longer interval? It's a judgment call. On one hand is evidence-based medicine's scepticism of anything not directly proven 'beyond reasonable doubt' in an RCT; on the other is a 'balance of probabilities' approach based upon the biology.
Based upon the biology, I'd eat my hat if the Pfizer vaccine is substantially less effective with a longer dose interval. Most vaccines induce stronger immune responses with longer intervals. A couple of examples below. There are more.
Regimes like the Ox/AZ use the same adenoviral vector to prime & boost so face 'anti-vector immunity' (immunity from the first dose to the viral 'postman' which must delivers the spike protein 'message' for the boost). This favours longer intervals specifically for Ad/Ad but...
...the above shows that longer intervals are better for regimes with different viral vectors, DNA priming, inactivated virus boosting - this isn't just an adeno effect. It's v rare for a 3wk interval to give stronger responses than 8+ wks (I can't think of examples, can you?)
Mechanistically, at 3w, the immune response to prime isn't complete- it hasn't yet produced all the memory B cells which give the best response to the boost. Once they are made, the memory cells last years! They won't forget how to respond to a boost in a few months.
I appreciate mechanistic arguments often prove to be wrong, and RCT evidence with Pfizer at longer intervals should definitely be produced ASAP... but as @zeynep has written in an excellent article today:
https://t.co/WrNVW5jRaW
There is a good debate:
@Bob_Wachter has written thoughtfully https://t.co/wZgvN937DV

@trishgreenhalgh @EricTopol @nataliexdean have all argued the other way from me - would welcome their thoughts on the above 🧵
I haven't yet seen a vaccine immunologist who has personally done experiments giving vaccines at different intervals and who is concerned about the longer interval... but I look forward to hearing that view too...

More from Government

Long thread: Because I couldn’t find anything comprehensive, I’m just going to post everything I’ve seen in the news/Twitter about Trump’s activities related to the Jan 6th insurrection. I think the timing & context of his actions/inactions will matter a lot for a senate trial.

12/12: The earlier DC protest over the electoral college vote during clearly inspired Jan 6th. On Dec 12th, he tweeted: “Wow! Thousands of people forming in Washington (D.C.) for Stop the Steal. Didn’t know about this, but I’ll be seeing them! #MAGA.”


12/19: Trump announces the Jan. 6th event by tweeting, “Big protest in D.C. on January 6th. Be there, will be wild!” Immediately, insurrectionists begin to discuss the “Wild Protest.” Just 2 days later, this UK political analyst predicts the violence


12/26-27: Trump announces his participation on Twitter. On Dec. 29, the FBI sends out a nationwide bulletin warning legislatures about attacks https://t.co/Lgl4yk5aO1


1/1: Trump tweets the time of his protest. Then he retweets “The calvary is coming” on Jan. 6!” Sounds like a war? About this time, the FBI begins visiting right wing extremists to tell them not to go--does the FBI tell the president? https://t.co/3OxnB2AHdr
Typically excellent piece from @dsquareddigest The exponential insight is especially neat. Think of it a little like fishing...today you can’t export oysters to the EU (because you simply aren’t allowed to), tomorrow you don’t have a fish exporting business (to the EU).


The extremely small minority of people who known anything about this who think that Brexit will be good for the City make a number of arguments which I shall address in turn...

1. They need us more than we need them. This is a variant of the German carmakers argument. And we know how that went...Business will follow the profit opportunity and if that has moved then so will the business...

And what do we mean by us / we. We’re not talking about massed ranks of Euro investing / trading etc blue blooded British institutions.

Au contraire. We’re talking about the London based subs of US, Asian and indeed European capital markets players...As soon as they think the profit opportunity has moved then so will they...it’s a market innit...

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शायद ही हमें कोई इसके पीछे का वैज्ञानिक कारण बता सके।

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हमारे ऋषि मुनि विद्वान थे, वे जो बात करते या कहते थे उसके पीछे कोई न कोई वैज्ञानिक कारण छुपा होता था।

एक बहुत रोचक तथ्य है पितृ पक्ष, भादो( भाद्रपद) प्रकृति और काक के बीच।

एक बात जो कह सकते कि हम सब ने स्वतः उग आये पीपल या बरगद का पेड़/ पौधा किसी न किसी दीवार, पुरानी

इमारत, पर्वत या अट्टालिकाओं पर ज़रूर देखा होगा। देखा है न?

ज़रा सोचिये पीपल या बरगद की बीज कैसे पहुंचे होंगे वहाँ तक? इनके बीज इतने हल्के भी नहीं होते के हवा उन्हें उड़ाके ले जा सके।