Research is showing AZ as your first vaccines then booster of Pfizer is actually the best combination. I don’t understand the hate for AZ but maybe I’m missing something.
Its still all massively political.
Where AZ may have helped the UK and hindered other is due to vaccine nationalism. Uptake is lower in areas which are arguably more nationalist in thinking (also economically related to a degree). The EU may have done us a favour by making it a nationalist issue whilst undermining public confidence in all vaccines though particularly AZ.
The result being that we have better coverage in some areas which comparative socio-economic areas in Europe perhaps dont have or it simply meant we were less hesitant that perhaps we would have been.
Also its hard to compare this directly with many countries. Germany not only allowed mixing vaccines but actively encouraged it because it was thought it gave better protection. Merkel herself had a combo of AZ and Pfizer.
However I don't think the T-Cell theory works. The real world study on waning immunity in the UK is based not on antibody levels but whether people get symptomic covid, severe covid requiring hospitalisation or die. So if T-Cell immunity was performing more than we realise, you'd see it in this data.
I think I might cavet that with a comment about how when it became apparent that AZ was under question you might have had a fair number of the most middle class and mobile actively and deliberately seeking out Pfizer over AZ by choice thus distorting things a little. This group would be more likely to be healthier and less at risk in the first place. But I still think if this happened its would be a minimal effect because I think most people were just bloody grateful to get anything if they were over 50.
I think one of the differences here was that we perhaps had a greater sense of urgency both because of cases/deaths but also because we had so many restrictions it seemed the most logical and quickest way to end them and AZ was available. The other and probably the most important factor was our timing of vaccines and the decision to do the 12 week gap which seems to improve immunity acquired and make it last for longer too - and thats applicable for both AZ and Pfizer. I think waning in the UK didn't seem to show up in the data for slightly longer than expected.
So I would generally dismiss that telegraph article as more telegraph nationalist nonsense rather than a scientific over sight.
AZ made a huge difference to us initially. Without it, we would have really struggled getting as many people vaccinated when cases were high and that stopped both deaths and transmission chains onward (meaning the R couldn't skyrocket even when things reopened in July when immunity levels were particularly high the most at risk groups). Nightclubs etc reopening in Europe has perhaps happened at a different point where immunity in the population overall is lower leading to more of a spike.
I think the decision not to use AZ again for boosters and instead use the more expensive and more difficult to source Pfizer because it has higher demand and is imported, really is the thing that shows where the UK scientific evidence is taking us and that talk of tcell immunity should perhaps be confined to the folder marked 'bollocks'.