Yellow Fever Infection is 40% Fatal in the Americas

Even with a vaccination requirement to visit most Yellow fever endemic countries, the Pan American Health Organization (PAHO) has issued a new Epidemiologic Alert regarding increased human cases in 2025.

As of March 26, 2025, the PAHO wrote that health officials have confirmed 131 Yellow fever (YF) cases in four countries, 53 of them fatal, indicating a 40.4% case-fatality rate. 

Brazil has 81 confirmed cases, 31 of which have been fatal.

The other YF cases have been reported in the Plurinational State of Bolivia, Colombia, and Peru.

In 2025, YF cases have also been detected in the state of São Paulo in Brazil and the department of Tolima in Colombia, regions outside the Amazon region.

The PAHO/WHO wrote '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.'

When departing to South America from the United States in March 2025, YF vaccination services are offered at most travel clinics and pharmacies. Once immunized, a certificate that is essential to enter certain countries will be generated.