Yellow fever cases reported in regions outside the Amazon regions of Brazil and Colombia in 2025
The Pan American Health Organization/World Health Organization (PAHO/WHO) in an Epidemiological Alert published March 26 reports an increase in human cases of yellow fever in 2025 in countries of the Americas Region to date.
During the first 12 epidemiological weeks of the year (Jan 1- March 22), 131 confirmed cases of yellow fever in humans have been reported in four countries of the Region- Bolivia, Brazil, Colombia and Peru.
Of the 131 human cases, 53 were fatal.
A breakdown of each country shows:
Bolivia- One case which was fatal.
Brazil- 81 cases, including 31 deaths.
Colombia- 31 cases, including 13 deaths and
Peru- 18 cases, including 8 deaths.
While yellow fever cases in the past were mainly reported throughout the Amazon region of these countries; however, in 2025, officials are also detecting cases in the state of São Paulo in Brazil and the department of Tolima in Colombia, regions outside the Amazon region of both countries.
In 2024, cases were reported primarily throughout the Amazon region of Bolivia, Brazil, Colombia, Guyana, and Peru.
According to experts, the risk of yellow fever outbreaks in the Americas is high.
PAHO/WHO encourages Member States with areas at risk to continue surveillance and vaccination efforts in endemic areas.
Medical history: 1918 influenza pandemic, Yellow fever in the US in the 18th and 19th centuries
It is essential that countries achieve vaccination coverage of at least 95% in populations in at risk areas, in a homogeneous manner, and that health authorities ensure that they have a strategic reserve inventory that allows them to maintain routine vaccination and, at the same time, respond effectively to possible outbreaks