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Yellow Fever


  1. Yellow Fever vaccine is required for entry into most S. American and many sub-Saharan African countries, and you must have documentation that you received Yellow Fever vaccine at least 10 days before entering.
  2. There are no guarantees that destination country officials will accept a Yellow Fever vaccine waiver, either denying entry, insisting on a 6–10d pre-entry quarantine of the traveler, or requiring on-site administration of the locally available version of the vaccine with local injection supplies (and a subsequent waiting period to allow for an immune response).
  3. Yellow Fever vaccine can only be given at state-certified sites for administration, and a traveler must have available a yellow card stamped with documentation of the date Yellow Fever vaccine was given (renewed every 10 years) to show immigration officials in destination countries.
  4. There are medical conditions which may tilt the risk/benefit balance away from Yellow Fever vaccination, in which case a medical waiver document may be provided to excuse the traveler from vaccination*. However, even with such risks for Yellow Fever vaccine related complications, if Yellow Fever virus activity is substantial at the destination, Yellow Fever vaccine may be given, unless travel can be postponed. This is a complex medical decision.*No guarantee such a waiver will be accepted by local officials at the destination (check with embassy).


Disease: A multi-organ illness, which can be mild or severe, caused by Yellow Fever virus and characterized by,

  1. Fever
  2. Headache
  3. Muscle/Joint Aches
  4. Jaundice (yellow eyes, skin, urine)
  5. Respiratory, liver, kidney failure
  6. Bleeding from multiple body sites
  7. Death (20-50%)

From exposure to illness onset is 3-6 days.



  • Sub-Saharan Africa and tropical South America
  • It is intermittently epidemic.
  • There are approximately 200,000 cases and 30,000 deaths annually.
  • Yellow Fever Incidence,
    • Africa – 1/2,000 for a 2-week stay, during high-risk season
    • S. America- 1/20,000
    • 0.5-5/1 Million travelers to endemic countries


Transmission: Aedes aegypti mosquito


Treatment: None



  1. Avoid mosquito bites,
    1. Stay in well-screened, air-conditioned spaces.
    2. Cover body with clothing.
    3. Insect repellent with DEET
    1. Vaccine (live virus)
      1. Single shot
      2. Must be given at a designated vaccine center and documented by signed stamp on “International Certificate of Vaccination or Prophylaxis” (yellow card) – this becomes valid 10 days after vaccination and is good for 10 years.
        1. Travelers without proof of vaccination or a written exemption waiver may be given the vaccine (with risk of exposure to needles contaminated with hepatitis B or C virus or HIV) on attempted country entry or detained (quarantined) up to 6-10 days.
      3. The vaccine is nearly 100% effective: only 1 case of Yellow Fever has been documented in a vaccinated traveler. Though immunity may persist for life, countries may still require a booster documented every 10 years.
      4. It is the only possibly routinely required vaccine; in Yellow Fever endemic countries or some countries giving passage to those who have come from a Yellow Fever country.
      5. Side-Effects
        1. Systemic mild reactions (1 in 4 persons): Fever, headache, muscle aches within 2-3 days and lasting 5-10 days
        2. Serious reactions,
          1. Immediate allergic reactions (especially those with serious egg allergies)
          2. Neurotropic disease (1/125,000): serious neurological problems, rarely fatal
          3. Viscerotropic disease (1/250,000): can be life-threatening and so far only seen in first-time Yellow Fever vaccinees.
      6. Precautions/Contraindications
        1. Less than 9 mo’s-old and 60 yrs and older (if have never received vaccine before).
          1. Those who have received the vaccine before 60 yrs-old probably are not at the increased risk for neurotropic or viscerotropic disease of the usual ≥ 60 yr-old.
          2. Yellow Fever vaccine can be given if truly high-risk of infection (such as Yellow Fever epidemic).
        2. Asymptomatic HIV infection with moderate immunosuppression (CD4 count 200-500; discuss with physician).
        3. Pregnancy/Breastfeeding: avoid unless high-risk travel
      7. Contraindications
        1. Children < 6 months (increased neurotropic disease risk)
        2. Anaphylactic allergic reaction to Yellow Fever vaccine, eggs, chicken protein, latex, gelatin
        3. Altered immune status: thymus disorder, myasthenia gravis, primary immune deficiency, malignant neoplasm, post organ transplant, immune suppressant or modulatory drugs, AIDS
      8. Yellow Fever Boosters: Yellow Fever Vaccine (YFV) Boosters: In April, 2013, the World Health Organization conducted that YFV, in the vast majority of patients, confers lifelong immunity. The every 10-year booster requirement expires from the International Health Regulations in June, 2016. The U.S. Centers for Disease Control and Prevention supports, with only a few defined exceptions requiring YFV boosters.

        However, Though YFV booster policy has changed medically, there may be a lag in adoption by individual countries out of ignorance or bureaucratic inertia. Therefore, it is a priority for the traveler to YF endemic countries or to other countries after passing through YF countries to ascertain the real-time policy of those countries with respect to up-to-date YF vaccination (within the prior 10 years) so as to not encounter problems entering such countries. Contacting their embassies pre-travel is advised if you do not update YFV status.

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