Yellow Fever Vaccine

What is yellow fever?

Yellow fever is a serious disease caused by the yellow fever virus. It is found in certain parts of Africa and South America. Yellow fever is spread through the bite of an infected mosquito. It cannot be spread person to person by direct contact. People with yellow fever disease usually have to be hospitalized. Yellow fever can cause:

• fever and flu-like symptoms
• jaundice (yellow skin or eyes)
• bleeding from multiple body sites
• liver, kidney, respiratory and other organ failure
• death (20 to 50% of serious cases)

Yellow fever vaccine is a live, weakened virus. It is given as a single shot. For people who remain at risk, a booster dose is recommended every 10 years.

Yellow fever vaccine may be given at the same time as most other vaccines.

How can I prevent yellow fever?

Yellow fever vaccine can prevent yellow fever. Yellow fever vaccine is given only at designated vaccination centers. After getting the vaccine, you should be given a stamped and signed ''International Certificate of Vaccination or Prophylaxis'' (yellow card). This certificate becomes valid 10 days after vaccination and is good for 10 years. You will need this card as proof of vaccination to enter certain countries. Travelers without proof of vaccination could be given the vaccine upon entry or detained for up to 6 days to make sure they are not infected. Discuss your itinerary with your doctor or nurse before you get your yellow fever vaccination. Consult your health department or visit CDC's travel information website at https://www.cdc.gov/travel to learn yellow fever vaccine requirements and recommendations for different countries.

Another way to prevent yellow fever is to avoid mosquito bites by:

• staying in well-screened or air-conditioned areas,
• wearing clothes that cover most of your body,
• using an effective insect repellent, such as those containing DEET.

Who should get yellow fever vaccine?

• Persons 9 months through 59 years of age traveling to or living in an area where risk of yellow fever is known to exist, or traveling to a country with an entry requirement for the vaccination.
• Laboratory personnel who might be exposed to yellow fever virus or vaccine virus.

Information for travelers can be found online through CDC (https://www.cdc.gov/travel), the World Health Organization (https://www.who.int), and the Pan American Health Organization (https://www.paho.org).

You should not donate blood for 14 days following the vaccination, because there is a risk of transmitting the vaccine virus through blood products during that period.

Who should not get yellow fever vaccine?

• Anyone with a severe (life-threatening) allergy to any component of the vaccine, including eggs, chicken proteins, or gelatin, or who has had a severe allergic reaction to a previous dose of yellow fever vaccine should not get yellow fever vaccine. Tell your doctor if you have any severe allergies.
• Infants younger than 6 months of age should not get the vaccine.
• Tell your doctor if: you have HIV/AIDS or another disease that affects the immune system; your immune system is weakened as a result of cancer or other medical conditions, a transplant, or radiation or drug treatment (such as steroids, cancer chemotherapy, or other drugs that affect immune cell function); or your thymus has been removed or you have a thymus disorder, such as myasthenia gravis, DiGeorge syndrome, or thymoma. Your doctor will help you decide whether you can receive the vaccine.
• Adults 60 years of age and older who cannot avoid travel to a yellow fever area should discuss vaccination with their doctor. They might be at increased risk for severe problems following vaccination.
• Infants 6 through 8 months of age, pregnant women, and nursing mothers should avoid or postpone travel to an area where there is risk of yellow fever. If travel cannot be avoided, discuss vaccination with your doctor.

If you cannot get the vaccine for medical reasons, but require proof of yellow fever vaccination for travel, your doctor can give you a waiver letter if he considers the risk acceptably low. If you plan to use a waiver, you should also contact the embassy of the countries you plan to visit for more information.

What are the risks from yellow fever vaccine?

A vaccine, like any medicine, could cause a serious reaction. But the risk of a vaccine causing serious harm, or death, is extremely low.

Mild Problems

Yellow fever vaccine has been associated with fever, and with aches, soreness, redness or swelling where the shot was given.

These problems occur in up to 1 person out of 4. They usually begin soon after the shot, and can last up to a week.

Severe Problems

• Severe allergic reaction to a vaccine component (about 1 person in 55,000).
• Severe nervous system reaction (about 1 person in 125,000).
• Life-threatening severe illness with organ failure (about 1 person in 250,000). More than half the people who suffer this side effect die.

These last two problems have never been reported after a booster dose.

What if there is a severe reaction?

What should I look for?

Look for any unusual condition, such as a high fever, behavior changes, or flu-like symptoms that occur 1 to 30 days after vaccination. Signs of an allergic reaction can include difficulty breathing, hoarseness or wheezing, hives, paleness, weakness, a fast heartbeat, or dizziness within a few minutes to a few hours after the shot.

What should I do?

• Call a doctor, or get the person to a doctor right away.
• Tell the doctor what happened, the date and time it happened, and when the vaccination was given.
• Ask your doctor to report the reaction by fi ling a Vaccine Adverse Event Reporting System (VAERS) form. Or you can file this report through the VAERS website at https://www.vaers.hhs.gov, or by calling 1-800-822-7967. VAERS does not provide medical advice.

How can I learn more?

• Ask your doctor. He or she can give you the vaccine package insert or suggest other sources of information.
• Call your local or state health department.
• Contact the Centers for Disease Control and Prevention (CDC) by calling 1-800-232-4636 (1-800-CDC-INFO), or by visiting CDC websites at https://www.cdc.gov/vaccines/resources/index.html