@ponderable saidNo, they do not have to leave. However, they will no longer have an arbitrary advantage over others that they should never have had.
...and the EU citizens who are dentsits have to leave now as not to take the Jobs away from the Britons.
There are plenty of qualified people from other countries - which have actually been friends to the UK - who will readily take the place of EU citizens unhappy with their equal status with those from outside the EU.
-Removed-All antibiotics can but those prescribed by dentists are more prone to that.
There is normally a warning on the bottle.
I had to discontinue the ones I was prescribed.
Then a week later, maybe two, when I was still screwed I had antibiotics from GP
to try and kill the bugs taking over my gut while not harming my friendly bugs.
It was not a pleasant few months and I wouldn't wish it on anyone ...