The World Health Organization reports (15 November 2018) no risk of yellow fever in Namibia. The government of Namibia requires proof of a yellow fever vaccination certificate for travellers arriving from or having transited through
countries with risk of yellow fever transmission.
Ministry of Home Affairs page states: "All visitors must also have a valid return ticket."
- Transit without visa with a confirmed onward ticket for a flight to a third country within 24 hours. Must stay in the international transit area of the airport and have documents required for the next destination.
U.S. policy on dual nationality can be found