The Center for Disease Control and Prevention (CDC) has released a notification requiring all Air Passengers entering the United States to carry a Negative COVID19 test.
This test needs to be taken at a center approved or authorized by the relevant national authority and should have been taken with in the last 72 hours of departure. If someone is traveling from a country which has a travel ban on account of COVID19, then, carrying the test result will not help – the ban will prevail.
It is important for travelers to check the latest requirement prior to embarking on a journey to the United States. The CDC press release can be found here.