Yellow fever update

Yellow fever cases continue to be reported in Africa and South America

Yellow fever (YF) is a viral disease spread by mosquitoes in parts of Africa, Central and South America, and in Trinidad in the Caribbean. YF infection can cause a serious (haemorrhagic) illness that can be fatal for humans. YF can be prevented by vaccination.

In Africa, the World Health Organization (WHO) advises that 34 countries either have a risk of YF in the whole country or have YF risk regions [1] and YF risk countries in Africa continue to report probable and confirmed YF cases. WHO also advise that in some African countries, there may be under-reporting of YF due to surveillance and data collection issues. The mosquitoes (Aedes spp.) that spread YF are common in many urban areas in Africa. This significantly increases the risk of YF spreading, especially in heavily populated areas like cities, which could lead to rapid YF outbreaks [2].

An increase in YF cases has been reported in a number of countries within South America in 2025. In 2024, a total of 61 confirmed YF cases (including 30 deaths) were reported in Bolivia, Brazil, Colombia, Guyana and Peru [3]. As of May 2025, a total of 235 confirmed YF cases have been reported (including 96 deaths) so far for 2025 [4], with cases reported in Bolivia, Brazil, Colombia, Ecuador and Peru [3, 4].

In 2024, most YF cases were reported in the Amazon region of Bolivia, Brazil, Colombia, Guyana and Peru. In contrast in 2025, while YF cases continue to be reported in this area, cases have also been reported outside the Amazon region, including in São Paulo State in Brazil and Tolima Department in Colombia [3].

This confirmed reporting of YF cases in a wider geographic area, including cases related to jungle transmission near urban centres, increases the risk of urban outbreaks [4].

Risk of YF outbreaks in South America remains high [3, 4]. While YF vaccination is one of the most successful public health interventions to prevent YF disease, the COVID-19 pandemic, among other factors, has led to a reduction of YF vaccine cover in the local population [3]. Most YF cases reported in 2024 and 2025 were in individuals not vaccinated against yellow fever [3, 4].

Advice for travellers

Before you travel

Check your risk of YF, vaccine recommendations and any certificate requirements at your destination using the TravelHealthPro Country Information pages.

WHO recommends YF vaccine for all travellers aged nine months and older visiting areas with risk of yellow fever [5] unless the vaccine is not advised for medical reasons.

You should also follow mosquito bite avoidance advice.

Some countries may require an International Certificate of Vaccination or Prophylaxis (ICVP) for yellow fever from travellers arriving in the country.

You must be aware that even if a country does not have a requirement for a YF ICVP, there could still be a risk of YF and YF vaccine may be recommended for your own personal protection.

For advice about your risk of yellow fever, certificate issues and to find out if yellow fever vaccine is suitable for you, we recommend you arrange an appointment with a designated Yellow Fever Vaccination Centre (YFVC).

In England, Wales and Northern Ireland, you can find your nearest YFVC using our online YFVC Search Locator. In Scotland, YFVCs can be located here.

Advice for health professionals

Health professionals should advise travellers about their destination specific risk of yellow fever according to TravelHealthPro Country Information pages.

Travellers to risk countries must be advised that yellow fever is spread via mosquito bites and carefully counselled about the importance of following insect bite avoidance measures day and night.

When undertaking yellow fever risk assessment, health professionals should use the Yellow fever pre-vaccination checklist and Yellow fever vaccine: contraindications and precautions reminder

Health professionals are also encouraged to access our Outbreak Surveillance section where outbreak details are posted. Please note that not all cases of disease or outbreaks are reported; some outbreaks may only be reported if they occur outside the usual recognised risk area or season, or they have been reported in greater than usual numbers.

Health professionals can also call the NaTHNaC Advice Line for further advice.