The new virus variant B.1.1.7 was already detected in Kent on Sept. 20 and again in London on Sept. 21, long before a vaccine was approved. The BioNTech/Pfizer vaccine was still in Phase III testing at that time.
Already in October and at the latest in November it was clear that this new variant appeared in more and more positively tested infected persons, i.e. it is more infectious than the old virus (just as it is noticeable that North Africans are involved in crimes much more often than North Europeans).
As late as the end of November, there was an appeal by dozens of scientists to tighten the lockdown partly because of this new virus.
However, Boris Johnson ignored it for the time being; after all, the Christmas shopping season brings in tax revenue.
Now it is probably opportune to somehow blame the impending blockade at the border due to the No Deal Brexit on the virus and the evil EU.
(The new virus variant has a striking number of mutations, including 6 significant mutations in the spike protein, which on the one hand makes it more difficult for the body’s immune defenses to detect the virus, and on the other hand increases the affinity for the ACE receptors, so less virus is needed to cause infection.
According to BionTech and other vaccine manufacturers, this is not a problem; the vaccine contains a whole series of spike protein sequences, so a few mutations are not a big deal.)