I never said that a longer gap would reduce longer term effectiveness, just that it was unlikely to provide any particular benefit, though the studies you've quoted do give pause for thought.
In glad you agree that long term effectiveness is more likely to be increased with a longer interval.
With the Pfizer vaccine at least, it feels like it'd be "tweaking around the edges" though when it's 95% effective* at the 3 week interval (presumably it's already higher with the 12 week interval) so chasing a handful of percent by delaying past 12 weeks seems, odd.
But surely it depends on what you re measuring efficacy against?
While I agree the only thing that really matters, in terms of ending the pandemic, is efficacy measured against severe symptoms, if you set the bar lower than that, such as being infectious, the efficacy is clearly lower than 95 per cent, so there is room for improvement.
I am not necessarily saying we hold be increasing the delay between doses, at least not at this stage, but I am keen to dispel the myth that a longer gap is in any way likely to be detrimental.
Putting it a different way, getting the 2nd dose of Pfizer in whatever timeframe will grant 95% efficacy, but I'd be surprised if the difference between having it at 3 weeks or 13 weeks is appreciable.
A trial is underway to determine that, but I'm glad you agree that such a wait is not a concern.
...it may have an effect is on the longer-term immunity mechanisms (Memory T & B cells) but a quick look hasn't turned up any studies on this.
Give it a few months and we should have more data on this.
I note though you've not said anything what I felt was the rather key point around pharmacies and vaccination centres going 'doubly off-label'. Whilst most of the people running the vaccine centres will obviously be highly trained individuals, I doubt that they have any particular additional-knowledge around immunology and vaccine mechanics above any well-read member of the public. I've happily supported going off-label by moving to 12 weeks as this has been backed by the UK's CMOs, a taskforce of vaccine experts, and increasing scientific consensus now, but my local GP going off-label because "they read a paper online that suggests it may work better" would set off alarm bells, regardless of how well intentioned unless I knew that they were a proper specialist in that area (which being a GP, they likely won't). That way quackery lies, I fear
*for all the clinical trail efficacies are worth, though numbers coming out of real-world studies are coming out in the same ballpark
I don't think my GP is going to deliberately wait, but there is no suggestion of this, is there?
I was addressing the fact that some people are concerned about the effects of a further delay.