Is There a Vaccine to Prevent Yellow Fever?
Yellow fever is a potentially fatal illness. People planning to travel to an area endemic for yellow fever should see their physician before travel, preferably at least six weeks before departure; preventive measures for other serious illnesses are also very important. Travelers should use mosquito-bite precautions, including wearing light, protective clothing and using window screens and bed nets when available. Insect repellants should be used and should contain DEET, picaridin, IR3535, or oil of lemon eucalyptus. Room sprays and insecticides may be used to reduce the mosquito population in sleeping areas.
Yellow fever vaccine is given at least 10 days prior to departure, is highly effective, and generally provides 10 years of immunity, after which a booster should be given in the setting of recurrent or ongoing exposure. Areas of risk may be found in the CDC Yellow Book chapter 3, under Viral Hemorrhagic Diseases (Figure 1 and Figure 2).
Yellow fever vaccine is recommended for all individuals over 9 months of age who reside or will be traveling in endemic areas of Latin America and Africa, as well as for entry into certain countries. Contraindications include age under 6 months, severe allergy to any of the vaccine components, or history of severe reaction to a dose of yellow fever vaccine.
Generally, yellow fever vaccine is well tolerated with only mild flu-like symptoms as a side effect. However, because yellow fever vaccine is a live attenuated virus vaccine, there is potential for infection from the vaccine itself in some populations. Conditions where risk versus benefit of the vaccine should be carefully weighed include people with HIV or other immunocompromised states such as thymus disorders, malignancy, transplantation, or treatment with corticosteroids, chemotherapy, and other immunosuppressants. Others include pregnancy, breastfeeding, age over 59, and age 6-8 months. Note that yellow fever vaccine virus is not shed by the recipient and poses no threat to others.
Adults 60 or over may be at increased risk of serious disease or death after yellow fever vaccine, especially with a first yellow fever vaccination. These individuals must discuss risks, itineraries, and other preventive measures above with their health-care professional.
In women of childbearing age, vaccination during pregnancy is unlikely to be a risk to the fetus but poses a theoretical risk of infection to the mother the closer she is to the third trimester, when her immunity is lowest. While birth defects have not been observed, out of caution most experts suggest a minimum two-week period of avoiding conception before receiving the yellow fever vaccination.
Yellow fever vaccine is given at least 10 days prior to departure and generally provides 10 years of immunity, after which a booster should be given in the setting of recurrent or ongoing exposure. In the U.S., yellow fever vaccine is given only in designated yellow fever vaccination centers. Travelers receive a yellow International Certificate of Vaccination card validated by the vaccination center and valid for 10 years. This card is required for entry to certain countries, even if only to change planes at the airport.