What should you know about yellow fever virus transmission?

The virus circulates between mosquitoes and people or other primates in areas where it is present. A mosquito can acquire the virus after feeding on an infected host and may pass it on through a later bite. Yellow fever does not spread through casual touch, sharing food, coughing, or sitting near someone who is ill.

Transmission risk depends on where you are, local mosquito activity, and whether you have protection before travel. Being outdoors during mosquito activity, particularly in forested or urban settings where the virus circulates, can increase exposure.

If you are travelling to an area with yellow fever risk, arrange a travel-health appointment early enough to discuss vaccination requirements and suitability. Wear covering clothing, use an appropriate insect repellent as directed, and stay in accommodation with screened or air-conditioned rooms when possible.

Check your itinerary carefully: risk and entry requirements can differ between destinations, including transit points. Keep your vaccination documentation with your travel papers if it is required for your journey.

Seek urgent medical assessment if you develop fever after travel to an area where yellow fever occurs, especially with severe headache, repeated vomiting, marked weakness, yellowing of the eyes or skin, unusual bleeding, confusion, or trouble breathing. Tell the clinician where and when you travelled and mention mosquito bites if known.

Ask whether your destinations create a yellow fever risk, whether vaccination is appropriate for you, how to manage mosquito exposure on your route, and what symptoms after travel should prompt urgent assessment. Discuss allergies, pregnancy, immune conditions, and medicines that may affect vaccine decisions.