"When your immune system fights an infection, it cranks up the mutation rate during antibody production by a factor of 1,000,000, and then has them compete with each other. This natural selection process creates highly specific antibodies for the virus."
But luckily there is not such a border bs going on. All part of the eu.
Where you can move your front door if you want to move your house from one country to the other if you have a house on top of one of all the boarders crisscrossing the town/towns :)