PAHO issues new epidemiological alert amid rising yellow fever cases in the Americas – PAHO/WHO
Washington, DC, March 31, 2025 (PAHO) – The Pan American Health Organization (PAHO) has issued a new epidemiological alert in response to an increase in cases of yellow fever in the Americas during the first months of 2025. The number of human cases confirmed from March 22 has more than duplicated compared to the total recorded in all 2024 disease expansion.
In the first almost three months of 2025, 131 human cases have been confirmed, with 53 deaths. In comparison, 61 cases were reported during 2024, 30 of which were fatal. The cases are found in Bolivia (1 case, 1 death), Brazil (81 cases, 31 deaths), Colombia (31 cases, 13 deaths) and Peru (18 cases, 8 deaths), with cases reported beyond the traditionally affected Amazon region.
Particularly worrying are the new cases reported since October 2024 in the department of Tolima, Colombia, indicating that the virus appears in areas not previously affected in recent years. In these regions, activities such as agriculture represent a risk factor for virus exposure. The increase in cases and its geographical propagation highlights the urgent need to strengthen surveillance, prevention and control measures to contain the disease.
In addition, the epidemiological situation in the state of São Paulo, Brazil, with 34 cases and 19 deaths, is worrying due to its proximity to densely populated urban centers, increasing the risk of a larger outbreak.
Yellow fever is a serious viral disease transmitted by mosquitoes, which can be fatal but can be prevented through vaccination. The vast majority of cases detected have involved people who were not vaccinated.
On an alert issued on March 27, the PAHO requires intensifying vaccination efforts in areas at risk, with the objective of coverage rates exceeding 95%. Vaccination is the most effective tool to combat the disease. Paho also recommends that countries review their vaccine actions, ensure rapid response plans for shoots and make sure that travelers to endemic areas are informed and vaccinated.
From the yellow fever epidemic in Brazil between 2016 and 2018, the public threat to the health of the disease has resurfaced in the Americas. The yellow fever virus remains in a silvatic cycle between specific species of non -human mosquitoes and primates in 13 countries and territories of the region. Since 1960, it has caused 9,591 human cases and 3,444 deaths.
In February, according to the increase in cases in several countries during the last months of 2024 and the first weeks of 2025, Paho published a risk assessment in which he considered that the risk of yellow fever outbreaks in the region was high.
The PAHO will continue to monitor the situation and support to countries to adopt the best strategies to prevent and control yellow fever.
