the ongoing outbreak in angola and the dr congo. the fractional dose would not qualify for a yellow fever certificate of vaccination for travelers. later studies found that the fractional dose was just as protective as the full dose, even 10 years after vaccination. as of february 2021, unicef reported awarded contract prices of ranging from us$0.97 to us$1.444 per dose under multi-year contracts with various suppliers. travel requirements risk countries (who designation) partial risk countries (who designation) vaccination against yellow fever 10 days before entering this country/territory is required for travellers coming from... all countries risk countries (including airport transfers) risk countries (excluding airport transfers) no requirement (risk country) no requirement (non-risk country)