One thing I don't understand is why we don't have a modified booster yet? The boosters being given are just a repeat of the vaccines given earlier in the year but they have always been less effective vs Delta
As I understand it:
1. A booster of the original is highly effective vs Delta, so why bother?
2. It's not yet clear if the drop in efficacy vs delta is due to lack of specificity vs delta, or that delta is just more transmissible. ie a delta specific vaccine may only offer marginal advantage as the delta advantage is from transmission, not immune escape.
3. A delta specific vaccine might be less effective against other variants whereas the original remains effective against all current variants.
4. Massive supply of the original is available.
Given the prevalence of the use of the AZ vaccine here, is this possibly why our cases are higher than anywhere else?
Certainly one possible factor.
We also have lower vaccination levels than many western European countries, particularly in children who have far more contacts than adults.
I've heard several experts commenting that the UK has far more of a return to pre- pandemic levels indoor mixing than most European countries, and this behavioural difference is the most obvious issue. But I'm not sure where the data for that comes from.
Most European countries have more mask wearing and more vaccine passport restrictions than us.
Anyone who says they know the exact reasons for differences between countries, or even within countries where there are also vast differences, is kidding themselves IMO.