Originally Posted by
Kacee
Perhaps you are unaware that (with limited exceptions at IAH and MIA) there are no international to international transits in the US. All arriving international passengers must clear immigration and customs and reclear security, regardless of their nationality. This applies to US citizens as well as citizens of other nations. It has nothing to do with whether the country from which they are arrivng is considered "clean" or not.
I am curious as to what flights are eligible at IAH. AFAIK, IAH cannot support airside transfers at all. They do have a connecting option right after immigration and customs that allows pax to teclear security in a special line. But other than that, I am unaware of this.