i am not current up on US policy, but up until a few years ago, HIV status did not prevent entry into the US, it just forced you to get an HIV Waiver. This basically had to show that you had a treatment facility lined up and payment planned for (or donated) so that you would not enter and become a burden to the public system. This system, as well as treatment of other communicable diseases such as TB, has been around for years and is very well regulated by CDC and DHS. While cumbersome and time consuming for the one with the disease, it is done to prevent spread in the US. The same policy applied to regular immigrants and refugees from all countries around the world.