As has been said, it was mentioned in at least Fallout 1 that Europe had by the time of the Final War degenerated into a frenzy of self immolation fighting each other and the Middle East. Plus the Obliteration of the Final War all but consumed the
Entire Planet, which if you look at it logically means that Europe, the Middle East etc would be reduced to smouldering ruins which if anyone was unlucky ? enough to survive would have their work cut out for them just to survive let alone even think about considering to try to find out how the rest of the world fared.
Basically when the Nukes flew the European countries were busy trying to bomb each other and the middle east back to the stone ages, so it's extremely doubtfull that there were many if at all any survivors.
Yes I am European but going by the Fallout Universe lore, it wouldn't make sense to base a Fallout Game in Europe given what is stated in the Lore, which includes 'expeditionary' forces from there as well in the guise of DLC.