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

Labour Grandees are listed in Sir Keir Starmer's colleague Jeffrey Epstein's ''Little Black Book''; Blair, Mandelson and Alastair Campbell. COINCIDENTLY, Keir Starmer and some of the same people have connections to ANOTHER of the worlds most prolific peadophiles. #StarmerOut


Starmer failed to bring charges against Jimmy Savile for paedophilia. The decision was made despite the Crown Prosecution Service receiving substantial evidence of his crimes from witnesses and victims several years before Savile died in 2011. #StarmerOut
https://t.co/PNyX5uSAkw


With a past like hers, Margaret Hodge might show a bit more humility.
In the Eighties Hodge was aware of previous child sex abuse in the care homes for which she was responsible, and did nothing about it. #LabourLeaks #StarmerOut

As leader of Islington Council, a post she held from 1982-92, Margaret Hodge was aware of previous, horrendous child sex abuse in the care homes for which she was responsible, and did nothing about it. #LabourLeaks #StarmerOut #CSA

She was guilty of rather more than a casual failure of oversight. In an open letter to the BBC after it investigated a range of monstrous abuse (child prostitution, torture, alleged murders), Hodge libelled one of its victims as “seriously disturbed”. #LabourLeaks #StarmerOut

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The benign product is sovereign programmable money, which is historically a niche interest of folks with a relatively clustered set of beliefs about the state, the literary merit of Snow Crash, and the utility of gold to the modern economy.

This product has narrow appeal and, accordingly, is worth about as much as everything else on a 486 sitting in someone's basement is worth.

The other product is investment scams, which have approximately the best product market fit of anything produced by humans. In no age, in no country, in no city, at no level of sophistication do people consistently say "Actually I would prefer not to get money for nothing."

This product needs the exchanges like they need oxygen, because the value of it is directly tied to having payment rails to move real currency into the ecosystem and some jurisdictional and regulatory legerdemain to stay one step ahead of the banhammer.