Yellow Fever Outbreaks

Authored by
Staff
Last reviewed
February 4, 2025
Content Overview
Yellow fever outbreaks in Africa, the Americas, and Oceania reported in 2025.

Yellow Fever Outbreaks 2025

Scientists believe yellow fever has existed for about 3,000 years, originating in Africa and spreading to the Americas in the 17th century. In the 18th and 19th centuries, yellow fever was considered one of the most dangerous infectious diseases. According to the World Health Organization (WHO), the yellow fever (YF) virus has become endemic in tropical areas of Africa and 13 countries in the Americas, such as Brazil. The WHO reported in 2025 that yellow fever's preliminary case fatality rate was 11%.

Africa Yellow Fever Outbreak

On March 28, 2024, the U.S. CDC issued a Level 2 Travel Health Notice regarding a yellow fever outbreak in Nigeria. In February 2024, the Republic of South Sudan's health ministry reported 48 suspected and two confirmed Yellow Fever cases from Yambio, Nzara, Tambura, Ibba, Ezo, and Maridi Counties of Western Equatoria State. Since the beginning of 2023, documented probable and confirmed cases of yellow fever have been reported in Burkina Faso, Cameroon, the Central African Republic, Chad, the Republic of the Congo, Côte d'Ivoire, the Democratic Republic of the Congo (DRC), Guinea, Niger, Nigeria, South Sudan, Togo and Uganda. The overall risk at the regional level was re-assessed as moderate. Between January 2024 and November 2024, a total of 29 confirmed YF cases were reported in Nigeria.

The Region of the Americas Yellow Fever Outbreaks

As of 2025, the Pan American Health Organization (PAHO) reported outbreaks in BoliviaBrazil, Colombia, Guyana, and Peru. Between epidemiological week (EW) 1 and EW 4 of 2025, 17 confirmed human cases of yellow fever have been reported in Brazil, Colombia, and Peru, of which seven have been fatal. In 2024, the PAHO confirmed 61 yellow fever cases, including 30 deaths, in the Americas. In Brazil, yellow fever transmission historically occurs within a sylvatic cycle in the Amazonian region. São Paulo State Health Department confirmed that 679 human cases were recorded from 2000 to 2023. Brazil experienced its largest recorded yellow fever outbreak in 2018. As of 2025, Australia, the U.S. CDCHong Kong, and the United Kingdom have issued travel alerts regarding Brazil's yellow fever outbreaks.

United States Yellow Fever Outbreaks

In the United States, the Butte County Mosquito and Vector Control District in California detected the Aedes aegypti (yellow fever) mosquito in 2023. For the fourth consecutive year, the Aedes aegypti was seen in Butte County. The American Society for Microbiology posts a history of the emergence of yellow fever outbreaks in the U.S.

Yellow Fever Vaccine Availability 2025

Various yellow fever vaccines are authorized as of 2025