From the Guidelines
The yellow fever vaccine provides lifelong immunity for most people after a single dose. While previously recommended every 10 years, the most recent evidence suggests that one dose provides lifetime protection for most individuals 1. However, certain groups may need a booster dose, including those who were initially vaccinated during pregnancy, before age 2, or while undergoing immunosuppressive therapy. People with HIV, those traveling to high-risk areas, or laboratory workers handling the virus may also require a booster. The vaccine works by introducing a weakened form of the yellow fever virus, allowing your immune system to develop antibodies without causing the disease. This creates immunological memory that remains effective for decades, as evidenced by studies demonstrating that YF vaccine immunity persists for many decades and might provide life-long protection 1. Some key points to consider include:
- The International Health Regulations previously required revaccination at intervals of 10 years to boost antibody titer 1.
- Evidence from multiple studies demonstrates that YF vaccine immunity persists for many decades and might provide life-long protection 1.
- Limited data suggest that revaccination occurring <10 years after the previous dose does not increase the risk for adverse events, particularly as serious adverse events occur primarily after the initial vaccination of YF vaccine 1.
- Side effects are typically mild and include soreness at the injection site, mild fever, and muscle aches lasting 5-10 days.
- The vaccine is contraindicated for infants under 6 months, people with severe egg allergies, immunocompromised individuals, and those with thymus disorders.
From the Research
Yellow Fever Vaccine Duration
The duration of immunity after yellow fever vaccination is a topic of interest, with various studies providing insights into its longevity.
- A single dose of yellow fever vaccine is highly immunogenic and confers sustained life-long protective immunity against yellow fever, as stated in a systematic review 2.
- The World Health Organization (WHO) has established that a single dose of the vaccine provides lifelong protective immunity, with neutralizing antibodies being the correlate of protection 3.
- A 10-year follow-up study found that older travelers (aged 60 years or older) who received a primary yellow fever vaccination were still seropositive, suggesting that a single vaccination is sufficient to convey long-lasting immunity for at least 10 years 4.
- Another study examined the long-term immunogenicity after yellow fever vaccination in immunosuppressed and healthy individuals, finding that immunosuppressive therapy did not affect the long-term persistence of neutralizing antibodies 5.
- However, some studies suggest that antiviral immunity may be lost in a portion of individuals within 5 to 10 years after a single vaccination, and that children may be at greater risk for primary vaccine failure 6.
Key Findings
- The majority of studies suggest that a single dose of yellow fever vaccine provides long-term immunity, with some studies indicating that it can last for 10 years or more 2, 3, 4.
- Immunosenescence may result in lower virus neutralizing antibody titers after primary vaccination and a more rapid waning immunity in older individuals 4.
- The use of immunosuppressive drugs after yellow fever vaccination does not appear to affect the long-term persistence of neutralizing antibodies 5.
- Some studies raise concerns about the potential for vaccine failures, particularly in children and individuals who receive a single dose of the vaccine 6.