Americans returning from all restricted countries will now be subject to a new arrivals process.
Foreign nationals are barred from entering the United States if they have been physically present in one of the designated restricted countries within 14 days before their attempted entry.
The United States Department of State recently made a number of significant changes to visa validity periods and application fees affecting Australian and French citizens.
Officials at US ports of entry have been authorized to conduct additional screening on individuals who present a known risk or individuals about whom more information is needed to make a determination of risk.
New powers are now in force allowing US officials to lawfully ask women travellers if they are pregnant and planning to give birth in the US.