Yellow Fever Vaccine
Yellow fever
Yellow fever is a hemorrhagic viral illness transmitted by Aedes mosquitoes in sub-Saharan Africa and tropical South America. Approximately 15% of patients who develop severe yellow fever will die. The disease can cause jaundice (hence 'yellow' fever), kidney failure, internal bleeding, and multi-organ failure. Vaccination is required for entry to many endemic countries.
Overall Benefit Score
Default scenario · 12-month-old · US community (92% vax rate)
Score for your child →The risk-benefit balance in your specific scenario suggests a detailed conversation with your child's provider before deciding.
📊 Evidence Scores
Scores computed from peer-reviewed data using VaxFact's evidence model. Based on default scenario (12-month-old, standard US community).
🦠 Disease Burden
Yellow fever is a hemorrhagic viral illness transmitted by Aedes mosquitoes in sub-Saharan Africa and tropical South America. Approximately 15% of patients who develop severe yellow fever will die. The disease can cause jaundice (hence 'yellow' fever), kidney failure, internal bleeding, and multi-organ failure. Vaccination is required for entry to many endemic countries.
Mild cases: fever, headache, muscle pain — resolves in 3–4 days. Severe cases (15% of initial cases progress): toxic phase with jaundice, hemorrhage, and multi-organ failure. Case fatality in toxic phase: 30–60%.
🛡️ Vaccine Effectiveness
Single dose provides lifelong immunity for the vast majority of recipients. WHO revised its position in 2013 — a single dose is now considered sufficient for life; boosters are no longer required. International Certificate of Vaccination (required for some country entry) is now valid for life.
Vaccine failures are extremely rare. The live attenuated 17D strain generates robust, lifelong neutralizing antibodies in >99% of recipients.
⚠️ Adverse Events & Side Effects
All probabilities are per 100,000 doses administered, sourced from VAERS, Vaccine Safety Datalink, and post-licensure surveillance studies.
Common Side Effects
Rare Serious Events
📅 Vaccine Schedule
Only administer at CDC-designated yellow fever vaccination centers. Contraindicated: age <9 months, severe egg allergy, immunocompromised, thymus disorders. Adults 60+: carefully weigh risk vs. benefit given higher YEL-AVD risk.
⚖️ Benefits vs. Considerations
✓ Benefits
- Single dose — lifelong protection against a hemorrhagic fever with 30–60% case fatality
- 85 years of use with well-characterized safety profile
- Required for entry to many endemic countries — mandatory for travelers
- 99% effectiveness against a disease with limited treatment options
- Eliminates risk of importing disease to non-endemic countries
↕ Considerations
- YEL-AVD (viscerotropic disease) can be fatal — risk increases dramatically with age 60+
- Contraindicated in infants under 9 months, immunocompromised individuals, severe egg allergy
- Only administered at authorized travel medicine centers — access limitation
- Produced in eggs — concerns for egg-allergic individuals
🔬 What Some Researchers Question
These are legitimate scientific debates — not fringe claims. They represent areas of ongoing research or policy disagreement among credentialed experts.
- The risk of YEL-AVD (yellow fever vaccine-associated viscerotropic disease) increases with age — reaching approximately 1–1.8 per 100,000 doses in adults over 60, compared with 0.4 per 100,000 in younger adults. With case fatality of 50–60%, this represents a meaningful risk for older travelers to low-risk destinations. Some travel medicine specialists advocate for careful individual risk assessment for older travelers rather than uniform recommendation (Thomas et al., 2011).
🌫️ Scientific Uncertainties
Honest acknowledgment of what we don't yet know with confidence.
- Exact mechanism and predictors of YEL-AVD — why some individuals develop this catastrophic reaction is not fully understood; thymus history and genetic factors suspected
- Risk-benefit balance for adults over 60 in non-endemic travel settings — where disease risk is low but adverse event risk is elevated
🌍 International Policy Comparison
How different countries approach this vaccine — revealing where global consensus is strong vs. where policy diverges.