The reason eggs are refrigerated in the USA and not in the EU is all about different methods of salmonella prevention. USA regulations have eggs externally was

The reason eggs are refrigerated in the USA and not in the EU is all about different methods of salmonella prevention. USA regulations have eggs externally washed and disinfected, and require they be kept at a low temperature for storage and transportation. The point of washing is to remove external salmonella contamination from the outside of the egg. The washing process removes some of the natural barrier from the egg and leaves it much more susceptible to bacteria penetrating through the shell and contaminating the egg, so they must be kept cool or refrigerated to help limit and slow the bacteria penetration process. Eggs are not refrigerated in Europe and are still generally healthy to eat. In most of the EU washing eggs is actually illegal, because it removes the protective coat that helps prevent bacteria from entering eggs. To prevent salmonella there have been some vaccination campaigns where EU chickens are mass vaccinated against salmonella (which is not a requirement in the US). I think in the UK you must have vaccinated all your egg producing chickens to be certified, but other countries are less strict. Refrigerating with or without the protective coat extends the shelf life.