Information on Yellow Fever

Yellow Fever - - Disease and Vaccine

Yellow fever occurs only in Africa and South America. In South America sporadic infections occur almost exclusively in forestry and agricultural workers from occupational exposure in or near forests.

In Africa the virus is transmitted in three geographic regions:

  • principally and foremost, in the moist savanna zones of West and Central Africa during the rainy season,
  • secondly, outbreaks occur occasionally in urban locations and villages in Africa,
  • and finally, to a lesser extent, in jungle regions.

Yellow fever is a viral disease transmitted between humans by a mosquito. Yellow fever is a very rare cause of illness in travelers, but most countries have regulations and requirements for yellow fever vaccination that must be met prior to entering the country. General precautions to avoid mosquito bites should be followed. These include the use of insect repellent, protective clothing, and mosquito netting. Yellow fever vaccine is a live virus vaccine which has been used for several decades. A single dose confers immunity lasting 10 years or more. Adults and children over 9 months can take this vaccine. Administration of immune globulin does not interfere with the antibody response to yellow fever vaccine. This vaccine is only administered at designated yellow fever vaccination centers; the locations of which can uproducts.)

  • Persons with an immunosuppressed condition associated with AIDS or HIV infection, or those whose immune system has been altered by either diseases such as leukemia and lymphoma or through drugs and radiation should not receive the vaccine. People with asymptomatic HIV infection may be vaccinated if exposure to yellow fever cannot be avoided.

    • If you have one of these conditions, your doctor will be able to help you decide whether you should be vaccinated, delay your travel, or obtain a waiver. In all cases, the decision to immunize an infant between 6 and 9 months of age, a pregnant woman, or an immunocompromised patient should be made on an individual basis. The physician should weigh the risks of exposure and contracting the disease against the risks of immunization, and possibly consider alternative means of protection.

    Medical Waivers

    Most countries will accept a medical waiver for persons with a medical reason for not receiving the vaccination. CDC recommends obtaining written waivers from consular or embassy officials before departure. Travelers should contact the embassy or consulate for specific advice. Typically, a physician's letter stating the reason for withholding the vaccination and written on letterhead stationery is required by the embassy or consulate. The letter should bear the stamp used by a health department or official immunization center to validate the International Certificate of Vaccination.

    Yellow Fever Vaccination requirements and recommendations for specific countries are available from the CDC Travelers' Health page.

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    Division of Vector-Borne Infectious Diseases
    National Center for Infectious Diseases
    Centers for Disease Control and Prevention
    Atlanta, GA


    URL: http://www.cdc.gov/ncidod/dvbid/yellowf.htm