Researchers collaborating through ISARIC have published a consensus of recommendations for identification and management of severe yellow fever from data collected using ISARIC tools.
Yellow fever is an acute viral haemorrhagic disease transmitted by mosquitoes. Initial symptoms appear three to six days after infection and include fever, chills, headache, muscle pain, and loss of appetite. Around a quarter of cases progress to severe illness, characterised by liver failure and jaundice, requiring intensive care. In Colombia, yellow fever has traditionally been confined to jungle regions. However, factors such as increased human activity and climate change has expanded its prominence.
Between 2024 and 2025, an outbreak in rural Colombia resulted in 37 confirmed cases and a preliminary mortality rate of 40.5%. The high mortality rate is linked to a lack of antiviral treatments available for the disease, as well as low vaccination rates amongst the affected population. This outbreak highlighted a need for a coordinated response to improve outcomes and strengthen preparedness for future yellow fever outbreaks.
Researchers collected data from patients being treated at Hospital Federico Acosta, Colombia, by using a tool developed through ISARIC to adapt the readily available dengue case report form (CRF). Once adapted, this new CRF was able to capture additional features of yellow fever patients. The data highlighted a clear evidence gap in clinical guidance for treating severe yellow fever.
To address this gap, a multidisciplinary panel of 12 experts conducted literature reviews of primary studies and systematic reviews of specific areas of treatment for severe yellow fever. They then identified key preliminary recommendations from these analyses, which were then peer reviewed by another panel member. Finally, a face-to-face meeting was held where final recommendations were reviewed and voted on.
Key findings:
- Using ultrasound as part of a broader monitoring plan helped guide early treatment decisions, which was important for managing severe yellow fever.
- Treatments like plasma exchange and continuous renal replacement therapy showed the strongest evidence for helping with liver failure and high levels of ammonia in the blood, which are associated with severe yellow fever.
- Steroids are still a key part of treatment for severe yellow fever, but more research is needed to confirm exactly how effective they are.
Dr Luis Felipe Reyes, Lead for ISARIC Member LIVEN Research Network and senior author on the paper said, “Using an adapted CRF was key to identifying gaps in clinical guidance for yellow fever. As a progressive and severe disease, it demands rapid, multidisciplinary care. This consensus presents an optimised, evidence-based approach and underscores the importance of continued research and strengthened prevention strategies.
We hope that the findings of this consensus will help shape national guidelines in future yellow fever outbreaks and result in optimised clinical outcomes.”
