Real Cause for Europe becoming the Pandemic's Epicenter for a 2nd Time ?

[Breadman]

WHO and others had already warned that Europe risked to have 700.000 or even more people severely hit by the virus during this winter long before the "omicron" variant emerges... And, already, Europe had anew become the Pandemic's Epicenter for a 2nd time.

>>> What's the real cause, then ?