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. Yellow fever vaccination and mosquito bite avoidance are important preventive measures against the disease.

Yellow fever is a risk in areas of 13 countries and territories in South and Central America. A high number of cases were reported from this region in 2025, with 346 confirmed human cases (including 143 deaths) from seven countries. This represents a 5.6-fold increase in cases compared to 2024 [1].

Since the beginning of 2026, a total of 41 confirmed cases (including 18 deaths) have been reported from four countries: Bolivia, Colombia, Peru and Venezuela.

In 2024, most YF cases were reported from the Amazon region. While YF cases continue to be reported in this area, cases have since been reported in a wider geographic area, outside the Amazon region. This includes in Sao Paulo State in Brazil and Tolima Department in Colombia [2]. In addition, reports suggest recent human YF cases in Venezuela have occurred in an area that had not previously been considered a risk for YF disease.

Risk of YF outbreaks in South America remains high [1–3]. An outbreak in Colombia has been ongoing since mid-2024, with 153 confirmed cases (including 62 deaths) reported [1]. The confirmed reporting of YF cases in a wider geographic area, including cases related to jungle transmission near to urban centres, increases the risk of urban outbreaks [1]. 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].

YF risk countries in Africa continue to report probable and confirmed YF cases. During 2024, confirmed cases of YF were reported in countries with no recent history of transmission and suboptimal vaccination coverage [4].

WHO also advise that in some African countries, there may be under-reporting of YF due to surveillance and data collection issues.

The risk of YF transmission remains high in endemic areas of Africa. The mosquitoes (Aedes spp.) that transmit YF are common in many urban areas in Africa. This significantly increases the risk of YF spreading, especially in heavily populated areas, which could lead to the rapid onset of YF outbreaks [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. Advice on general health risks, prevention advice, other vaccine recommendations, and malaria advice is also available on these pages.

Comprehensive travel insurance is recommended for all travellers.

YF vaccine is recommended for all travellers aged nine months and older, travelling to a country or area with a risk of yellow fever transmission (unless the vaccine is not advised for medical reasons).

Some countries may require an International Certificate of Vaccination or Prophylaxis (ICVP) for yellow fever from travellers arriving in the country [6].

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

You should also follow mosquito bite avoidance advice.

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 the UK, you can find your nearest YFVC using our online YFVC Search Locator. In Scotland, YFVCs can also 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.

In addition to the risk of yellow fever, travellers may be exposed to other vaccine- and non-vaccine preventable diseases, including malaria. Travellers should be made aware of these risks and advised accordingly.

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