Yellow fever

Last updated: June 9, 2023

Summarytoggle arrow icon

Yellow fever is an acute viral infection caused by the yellow fever virus. Primates are the main reservoir of the virus, which is usually transmitted through bites from infected mosquitoes. Yellow fever is endemic in large parts of South America and Africa. The incubation period is 3–6 days, and the majority of affected individuals remain asymptomatic or experience only mild symptoms. Symptomatic patients initially present with nonspecific symptoms such as sudden-onset fever, malaise, headaches, chills, nausea, and myalgia. Approx. 15% of these patients progress to the most serious stage of the disease, which can present with life-threatening hemorrhagic fever and organ failure. There is no causal treatment available, making prevention of crucial importance. A single dose of live-attenuated vaccine provides lifelong protection for most individuals.

Epidemiologytoggle arrow icon

  • Yellow fever is endemic in tropical regions of South America and Sub-Saharan Africa.
  • Asia, Europe, North America, and Australia are free of yellow fever (except for occasional imported cases).

Yellow fever is endemic in large parts of South America and Africa.


Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon


Clinical featurestoggle arrow icon

  • Incubation time: 3–6 days
  • Clinical features

Most patients remain asymptomatic or experience only mild symptoms.


Diagnosticstoggle arrow icon

The best test to rule out yellow fever infection is PCR, particularly in the absence of overt symptoms such as fever, headaches, and chills.


Differential diagnosestoggle arrow icon

The differential diagnoses listed here are not exhaustive.

Treatmenttoggle arrow icon

  • Symptomatic treatment
  • No specific antiviral treatment is available

Avoid NSAIDs that increase the risk of bleeding (e.g., aspirin, ibuprofen, naproxen) in patients with confirmed or suspected yellow fever infection!


Complicationstoggle arrow icon

We list the most important complications. The selection is not exhaustive.

Preventiontoggle arrow icon

Vaccination [2][6][7]

When contraindications are present, consider the individual's specific risks and benefits and use shared-decision making to decide whether to immunize.

If state supplies of yellow fever vaccine are limited, direct international travelers to the following CDC website ( for US providers of imported, non-FDA approved yellow fever vaccines. [7]

Referencestoggle arrow icon

  1. Jorgensen JH, Pfaller MA. Manual of Clinical Microbiology. ASM Press ; 2015
  2. Yellow Fever. Updated: June 12, 2017. Accessed: August 23, 2017.
  3. Transmission of Yellow Fever Virus . Updated: August 13, 2015. Accessed: August 20, 2017.
  4. Travelers' Health - Yellow Fever. Updated: July 10, 2015. Accessed: March 24, 2017.
  5. Yellow Fever - Symptoms and Treatment. Updated: August 13, 2015. Accessed: August 23, 2017.
  6. Yellow Fever Vaccine. Updated: August 13, 2015. Accessed: August 23, 2017.
  7. AAP Committee on Infectious Diseases. Red Book: 2021–2024 Report of the Committee on Infectious Diseases. American Academy of Pediatrics ; 2021
  8. Yellow Fever Vaccine Recommendations. Updated: April 21, 2021. Accessed: May 11, 2023.

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 Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer