What distinction do these 14 countries share ?

The USA, Brunei, Egypt, Iraq, Yemen, Malaysia, Oman, Qatar, Singapore, Sudan, South Korea, Tunisia, Turks & Caicos Islands and the United Arab Emirates.

Stumped ?

They all still ban foreigners from visiting and migrating specifically on the basis of an HIV-positive status.

And how do they find out who is positive if the person does not declare it, you might ask ? By random bag searches at the borders. Anyone found with their HIV medications, which have to be taken at least once daily without fail, is sent back.