How often is the yellow fever vaccine (YFV) required?

Yellow Fever Vaccine Administration Frequency

Yellow fever vaccination requires a single dose that provides long-lasting immunity, with International Health Regulations (IHR) requiring revaccination at intervals of 10 years to boost antibody titers for international travel purposes. 1

Primary Vaccination and Duration of Protection

• A single subcutaneous injection of 0.5 mL of reconstituted yellow fever vaccine provides strong initial immunity 1
• Evidence from multiple studies demonstrates that yellow fever vaccine immunity persists for many decades and might provide life-long protection 1
• A systematic review found that a single dose of yellow fever vaccine is highly immunogenic and confers sustained life-long protective immunity against yellow fever 2

Booster Dose Requirements

• International Health Regulations (IHR) require revaccination at 10-year intervals for international travel purposes 1
• To minimize adverse events and optimize immune response, efforts should be taken to observe a 10-year interval between yellow fever vaccine doses 1
• If the date of the most recent vaccination cannot be ascertained and the patient requires vaccination, a booster dose should be administered 1

Special Considerations

Age-Related Factors

• All older travelers (aged 71-85 years) remained seropositive 10 years after primary vaccination administered at age ≥60 years, suggesting a single dose provides long-lasting immunity for at least 10 years in this population 3
• However, adults aged 60 years and older have an increased risk of serious adverse events following vaccination and should discuss risks and benefits with their healthcare provider 4

Potential Concerns About Single-Dose Strategy

• Some research suggests that antiviral immunity may be lost in 1-in-3 to 1-in-5 individuals within 5 to 10 years after a single vaccination 5
• Children may be at greater risk for primary vaccine failure 5
• Recent epidemiological data shows vaccine failures particularly evident at >10 years after vaccination 5

Practical Considerations

• The vaccine must be administered at an approved Yellow Fever Vaccination Center, and travelers should receive an International Certificate of Vaccination or Prophylaxis (ICVP) as proof 4
• The Centers for Disease Control and Prevention recommends that yellow fever vaccination should be administered at least 10 days before travel to be valid for entry requirements 4
• Vaccination may still be required if arriving from a country with risk of yellow fever transmission or if transiting through a country with yellow fever risk for more than 12 hours 4

Administration Guidelines

• If the vaccine is administered inadvertently via the intramuscular route rather than the recommended subcutaneous route, the response to vaccine will likely not be affected, and repeating the dose is not necessary 1
• Persons should defer blood donation for 2 weeks after receiving yellow fever vaccine due to documented transfusion-related transmission of yellow fever vaccine virus 1
• Yellow fever vaccine should be administered either simultaneously or 30 days apart from other live viral vaccines 1