Yellow Fever Vaccine Information

Information about yellow fever vaccine for travelers

Yellow fever primarily occurs only in Africa and South America. It is a viral disease transmitted between humans by a mosquito. Illness ranges in severity from an influenza-like syndrome to severe hepatitis and hemorrhagic fever.

Yellow fever is preventable by a relatively safe, effective vaccine. Adults and children over 9 months of age can take this vaccine. International regulations require proof of vaccination for travel to and from certain counties. Vaccinees should receive a completed International Certificate of Vaccination, signed and validated with the physician's stamp where the vaccine was given. This certificate is valid 10 days after vaccination and for a subsequent period of 10 years.

For more information about yellow fever, please visit the following websites:

CDC's Yellow Fever Site

Who Should Not Receive the Yellow Fever Vaccine?

Yellow fever vaccine generally has few side effects; fewer than 5% of vaccinees develop mild headache, muscle pain, or other minor symptoms 5 to 10 days after vaccination. Under almost all circumstances, there are four groups of people who should not receive the vaccine unless the risk of yellow fever disease exceeds the small risk associated with the vaccine. These people should obtain either a waiver letter prior to travel or delay travel to an area with active yellow fever transmission:

Yellow fever vaccine should never be given to infants under 6 months of age due to a risk of viral encephalitis (inflammation of the brain) developing in the child. In most cases, vaccination should be deferred until the child is 9 to 12 months of age.
Pregnant women should not be vaccinated because of a theoretical risk that the developing fetus may become infected from the vaccine.
Persons hypersensitive to eggs should not receive the vaccine because it is prepared in embryonated eggs. If vaccination of a traveler with a questionable history of egg hypersensitivity is considered essential, an intradermal test dose may be administered under close medical supervision. (Notify your doctor prior to vaccination if you think that you may be allergic to the vaccine or to egg products.)
Persons with weakened immune systems 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, consult with your doctor. In all cases, the decision of whether or not to immunize should be made on an individual basis.

Medical Waivers to Yellow Fever Vaccine (only)

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.

Last Updated: July 13, 2010

The purpose of this web site is both educational and informative.
Personal medical advice should be sought from your local health department or physician.

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