yellow fever vaccine

Yellow fever vaccine is a live, weakened (attenuated) viral vaccine administered for the prevention of yellow fever, a viral infection caused by flavivirus, transmitted by mosquito bites.

Yellow fever vaccine is administered into the tissue under the skin (subcutaneous) to individuals above 9 months old who are residents of, or travelers to yellow fever endemic regions, including tropical areas of Africa and Central and South America. In addition to the vaccination, it is advisable to take precautions against mosquito bites in endemic regions.

Yellow fever infections are asymptomatic in most people, but in some people who develop the disease, it can cause fever, headache, body pain, nausea, and vomiting. In some people yellow fever can be life-threatening with damage to multiple organs including the liver, kidneys, brain, and gastrointestinal tract, with jaundice, renal failure, hemorrhage and shock. Studies suggest that the mortality rate in serious yellow fever disease is typically 20% or higher.

Yellow fever vaccine is prepared by culturing the 17D-204 strain of yellow fever virus in living avian leukosis virus-free (ALV-free) chicken embryos. Yellow fever vaccine causes a mild infection at the injected site which elicits an immune response from the body and the production of antibodies, which prevent disease when exposed to the wild-type yellow fever virus. Yellow fever vaccine also contains substances that preserve and stabilize the vaccine, and enhance immune response.

Yellow fever vaccine is used for the prevention of yellow fever in:

• Persons living in or traveling to endemic areas
• Persons traveling internationally through countries with yellow fever
• Laboratory personnel who handle virulent yellow fever virus or concentrated preparations of the yellow fever vaccine virus strains

• Do not administer yellow fever vaccine to:
  • Anyone with a history of hypersensitivity to chicken eggs or any component of the vaccine
  • Infants under 6 months (per CDC if exposure to the yellow fever virus is unavoidable)
  • Infants under 9 months (per manufacturer due to risk of encephalitis)
  • People with acute or febrile disease
  • People with compromised immunity due to cancer, radiation, or medications
  • Breastfeeding women
• Do not administer the yellow fever vaccine by routes other than subcutaneous injection.
• Yellow fever vaccine may not protect 100% of individuals.
• Yellow fever vaccine may cause severe allergic reactions including anaphylaxis even in persons with no prior history of hypersensitivity to the vaccine components. Vaccination must be administered in a facility that has appropriate medical treatment and supervision is available to manage anaphylactic reactions.
• Individuals with less severe or localized manifestations of allergy may receive the vaccination. Perform a hypersensitivity screening test in individuals with suspected or known egg allergy.
• There have been reports of fainting (syncope) following vaccination. Appropriate procedures should be in place to prevent falling and injury and to manage syncope.
• There have been reports of vaccine-associated viscerotropic disease (YFV-AVD) following the first dose of the yellow fever vaccine.
  • YFV-AVD can cause multi-organ failure or symptoms similar to fulminant wild-type yellow fever virus infection, including potentially fatal liver failure and internal hemorrhage.
  • People older than 60 years are at a higher risk and should be vaccinated after weighing the risks and benefits of vaccination and the risk of exposure to the yellow fever virus.
• There are reports of yellow fever associated neurotropic disease (YFV-AND), also known as post-vaccinal encephalopathy, primarily in first-time vaccine recipients. People older than 60 years, and immunosuppressed persons are at greater risk and should be vaccinated after weighing the risks and benefits of vaccination and the risk of exposure to the yellow fever virus.

Common side effects of yellow fever vaccine include:

• Headache
• Feeling unwell (malaise)
• Chills
• Fever
• Weakness (asthenia)
• Muscle pain (myalgia)
• Injection site reactions including:
  • Pain
  • Redness (erythema)
  • Swelling (edema)
  • Blister
  • Residual mass
  • Hypersensitivity
• Hypersensitivity reactions including:
  • Rash
  • Hives (urticaria)
  • Asthma
  • Severe allergic reaction (anaphylaxis)
• Acute disseminated brain and spinal cord inflammation (encephalomyelitis)
• Cranial nerve palsy
• Guillain-Barre syndrome, a condition in which the immune system attacks nerves

Rare side effects of yellow fever vaccine include:

• Vaccine-associated neurotropic disease
• Vaccine-associated viscerotropic disease including multi-organ failure

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

• Serious heart symptoms include fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness;
• Severe headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
• Severe nervous system reaction with very stiff muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, and feeling like you might pass out; or
• Serious eye symptoms include blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights.

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

Injection (17D-204 strain)

• At least 4.74 log 10 plaque-forming units/0.5 ml

Yellow Fever

Adult:

• Prophylaxis: 0.5 ml subcutaneously at least 10 days before travel
• A single, lifetime dose of yellow fever vaccine is sufficient for most people traveling to endemic areas, although some high-risk groups may benefit from a booster dose according to the Center for Disease Control and Prevention's Advisory Committee on Immunization Practices

Pediatric:

• Infants over 6 months (off-label): 0.5 mL subcutaneously for 1 dose at least 10 days before travel
• Infants over 9 months: 0.5 mL subcutaneously for 1 dose at least 10 days before travel
• A single, lifetime dose of yellow fever vaccine is sufficient for most people traveling to endemic areas, although some high-risk groups may benefit from a booster dose according to the Center for Disease Control and Prevention's Advisory Committee on Immunization Practices

Booster/additional dose for high-risk groups

• A single primary dose of the yellow fever vaccine provides long-lasting protection and is adequate for most travelers
• Additional doses of the yellow fever vaccine recommended for
  • Women who were pregnant (regardless of trimester) when they received their initial dose of yellow fever vaccine should receive 1 additional dose before travel, which puts them at risk for yellow fever virus infection
  • Persons who received a hematopoietic stem cell transplant after receiving a dose of the yellow fever vaccine and who are sufficiently immunocompetent to be safely vaccinated should be revaccinated before travel, which puts them at risk for yellow fever virus infection
• Booster dose for high risk after 10 years
  • A booster dose may be given to travelers who received their last dose of yellow fever vaccine at least 10 years previously and who will be in a higher-risk setting based on season, location, activities, and duration of their travel
  • Persons who were infected with HIV when they received their last dose of the yellow fever vaccine should receive a dose every 10 years
  • Travelers who plan to spend a prolonged period in endemic areas or those traveling to highly endemic areas such as rural West Africa during peak transmission season or an area with an ongoing outbreak
  • Laboratory workers who routinely handle wild-type yellow fever virus should have yellow fever virus-specific neutralizing antibody titers measured at least every 10 years to determine if they should receive additional doses of the vaccine
  • For laboratory workers who are unable to have neutralizing antibody titers measured, the yellow fever vaccine should be given every 10 years as long as they remain at risk

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

• Severe interactions of yellow fever vaccine include:
  • belimumab
  • certolizumab pegol
  • ibrutinib
  • ifosfamide
  • ixekizumab
  • lomustine
  • mechlorethamine
  • melphalan
  • methotrexate
  • onasemnogene abeparvovec
  • oxaliplatin
  • procarbazine
  • secukinumab
  • ustekinumab
• Yellow fever vaccine has serious interactions with 64 different drugs.
• Moderate interactions of yellow fever vaccine include:
  • anthrax immune globulin
  • belatacept
  • betibeglogene autotemcel
  • obinutuzumab
• Minor interactions of yellow fever vaccine include:
  • chloroquine

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

• There are no animal reproductive studies and no information is available if the yellow fever vaccine can cause fetal harm if used during pregnancy. Yellow fever vaccine should be administered to pregnant women only if travel to an endemic area is unavoidable, and the infant should be monitored after birth.
• After receiving the yellow fever vaccine, women of pregnancy potential should avoid getting pregnant for 4 weeks.
• Yellow fever vaccine should not be administered to nursing mothers because of the potential for serious risks to the breastfed infant, including brain inflammation (encephalitis). The decision should be made to discontinue nursing or not to administer the vaccine, after considering the importance of the drug to the mother.

• Before traveling to yellow fever endemic regions, obtain information regarding vaccination requirements by consulting your health care provider, travel agent, or the airlines. Such requirements may be strictly enforced for entry into certain countries, particularly for persons traveling from Africa or South America to Asia.
• Additional information is available from local health departments, the Centers for Disease Control and Prevention (CDC), and World Health Organization (WHO).
• When in a yellow fever endemic region, take precautions to protect yourself from mosquito bites by using insect repellent, wearing long-sleeved shirts and long pants, and staying in well-screened or air-conditioned areas.