From the PAHO epidemiological alert March 13, 2026: “In 2025, a total of 346 confirmed yellow fever cases and 143 deaths were reported across seven countries in the Region: Bolivia (8 cases, 2 deaths), Brazil (120 cases, 48 deaths), Colombia (125 cases, 46 deaths), Ecuador (11 cases, 8 deaths), Guyana (1 death), Peru (49 cases, 19 deaths), and Venezuela (32 cases, 19 deaths). During the first seven weeks of 2026, 34 human cases and 15 deaths have already been confirmed in Bolivia, Colombia, Peru, and Venezuela.
PAHO noted that the sylvatic transmission cycle of yellow fever, involving mosquito vectors and nonhuman primates as hosts, reactivates periodically in the region, which is an expected phenomenon. However, since late 2025, human cases have been detected in geographic areas without recent transmission and outside previously considered risk zones, such as São Paulo state in Brazil and the department of Tolima in Colombia.”
Most cases in 2025 and 2026 were reported in non-vaccinated people. 2025 is the year with the highest case numbers after the strong peaks in 2017 /2018. The figures result in a case-fatality rate of 41% in 2025.
PAHO recommends affected countries to maintain vaccination coverage of at least 95% in exposed populations.
Confirmed cases of yellow fever in humans by year in the Americas Region, between 2016 and 2026 (Source: 2026-march-13-phe-epidemiological-alert-yellow-fever-final.pdf):