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Content current as of October 12, 2026. AI-assisted draft; not yet reviewed by a licensed pharmacist. Current CDC schedules: immunization schedules.
- The disease and why it matters
- Video and figures
- Get CE credit
- Products available
- Who should get it
- Dosing and schedule, including catch-up
- Administration
- Storage and handling
- Contraindications and precautions
- Safety and adverse events
- Special populations
- Counseling pearls for the pharmacy counter
- Common patient questions
- References
The disease and why it matters
Yellow fever (YF) occurs in sub-Saharan Africa and tropical South America, where it is endemic and intermittently epidemic; most infected people have minimal or no symptoms, but about 12% of symptomatic patients progress after a brief remission to a severe form with hemorrhagic symptoms, jaundice, shock and multisystem organ failure, and the case-fatality rate for severe cases is 30% to 60%. [1]
The incubation period is typically 3 to 6 days; the initial illness is non-specific (backache, chills, fever, headache, myalgia, nausea and vomiting, prostration). There is no medicine to treat or cure yellow fever. [1] [2]
YF virus transmission in Africa is seasonal, increasing in West Africa during the middle of the rainy season (around August) and peaking in the early dry season (October); in South America the risk of sylvatic infection is greatest during the rainy season (January to May, peak February and March), and Aedes aegypti can transmit YF virus episodically in both rural and urban areas, even in the dry season. [1]
During 1970 to 2015, 11 cases of YF were reported in travelers from the United States and Europe to West Africa (6) or South America (5), and 8 (73%) died; only 1 had a documented history of YF vaccination and survived. [1]
Video and figures
Video
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Products available
CDC states that only one YF vaccine (YF-VAX, Sanofi Pasteur) is licensed for use in the United States; all YF vaccines currently manufactured are live-attenuated viral vaccines, and shortages of YF-VAX have occurred, during which Stamaril (a comparable vaccine made by Sanofi Pasteur in France) was imported under an expanded-access investigational new drug protocol from 2015 to 2021. [1]
| Item | Statement |
|---|---|
| Vaccine | 17D live-attenuated; YF-VAX (Sanofi Pasteur) [1] |
| FDA-approved use | Active immunization for the prevention of yellow fever in persons 9 months of age and older: persons living in or traveling to endemic areas, persons traveling internationally through countries with yellow fever, and laboratory personnel [3] |
| Dose, route, schedule | 0.5 mL subcutaneous; 1 dose; available in single-dose and multiple-dose (5-dose) vials per CDC [1] |
| Distribution | In the US, supplied only to designated Yellow Fever Vaccination Centers authorized to issue certificates of yellow fever vaccination [3] |
The FDA label posted for YF-VAX lists a two-vial presentation (lyophilized powder, Vial 1, and Sodium Chloride Injection USP diluent, Vial 2) in cartons of 5 single-dose vials, and the FDA page is marked content current as of 05/23/2025; the posted label is an older-format document with no revision date, and its how-supplied table shows cartons of 5 single-dose vials, while CDC's table also lists multiple-dose (5-dose) vials. [3] [4] [1]
Who should get it
CDC (Yellow Book 2026, yellow fever chapter)
As of April 23, 2025
YF vaccine is recommended for people aged 9 months and older who are living in or traveling to areas with risk for YF virus transmission in Africa or South America; some countries require proof of YF vaccination for entry, and because of the risk of serious adverse events, healthcare professionals should only vaccinate people at risk for YF virus exposure. [1]
CDC VIS (April 1, 2020 edition)
As of April 1, 2020
The VIS says YF vaccine is recommended for people 9 months through 59 years of age traveling to or living in areas at risk for yellow fever virus activity, or traveling to a country with an entry requirement for vaccination; people younger than 9 months or older than 59 years who are at increased risk might receive it in some situations. [2]
The Yellow Book says "epidemiologic silence" does not mean absence of risk, so travelers should not visit endemic areas without protective measures; a traveler's risk depends on immunization status as well as destination-specific and travel-associated factors. [1]
When no YF risk exists in the itinerary but country entry requirements are in effect, the vaccine risk outweighs the disease and avoiding vaccination with a medical waiver is reasonable, in deliberation with the patient. [1]
Dosing and schedule, including catch-up
Administer a single subcutaneous injection of 0.5 mL of reconstituted vaccine; a single dose of YF vaccine provides long-lasting protection to most healthy individuals. [3]
The International Certificate of Vaccination or Prophylaxis becomes valid 10 days after vaccination with YF-VAX; WHO's Strategic Advisory Group concluded in 2014 that a single primary dose provides sustained immunity and lifelong protection and that revaccination is not needed, the 2016 International Health Regulations amendment specifies that a completed certificate is valid for the lifetime of the vaccinee, and countries cannot require proof of revaccination if the last vaccination was more than 10 years prior. [3] [1]
ACIP recommends additional doses for: women who were pregnant at their initial dose (one additional dose before they are next at risk); people who received a hematopoietic stem cell transplant after a dose (revaccinate if sufficiently immunocompetent); and people living with HIV when they received their last dose (a dose every 10 years if they continue to be at risk). A booster can be considered for travelers whose last dose was 10 or more years ago and who are going to higher-risk settings (prolonged stays, peak season, ongoing outbreaks). [1]
Fractional dosing
As of April 23, 2025
CDC says that in the United States FDA has not approved fractional dosing of YF vaccine; WHO notes that fractional dosing does not meet YF vaccination requirements under the International Health Regulations, so proof of vaccination for international travel cannot be issued to a person who received only a fractional dose and revaccination would be recommended for those at risk. [1]
Outbreak use abroad
As of April 23, 2025
Several countries have extended vaccine supplies during large YF outbreaks by administering partial doses (usually 0.1 mL); limited data showed the immune response to a fractional dose was comparable to a full dose at one month and one year in healthy persons 2 years and older, with knowledge gaps remaining. [1]
Administration
- Give a single 0.5 mL subcutaneous injection of reconstituted vaccine; do not give intravascularly, intramuscularly or intradermally. [1] [3]
- Reconstitute with only the supplied diluent (0.6 mL of Sodium Chloride Injection USP for a single-dose vial); allow the reconstituted vaccine to sit for one to two minutes and swirl until a uniform suspension is achieved, avoiding vigorous shaking, and do not dilute; the vaccine is pinkish before reconstitution and a slight pink-brown suspension afterward. [3] [1]
- If the wrong diluent is used, contact the manufacturer to determine if and when revaccination is needed; do not use any other product as a substitute diluent. [1]
- Inactivated vaccines can be given at any time before or after YF vaccine; ACIP recommends YF vaccine be given at the same time as other live viral vaccines, otherwise wait one month; whenever possible give YF and MMR vaccines one month apart, although coadministration is acceptable if necessary before travel. [1]
- Oral Ty21a typhoid vaccine (Vivotif) can be given simultaneously or at any interval before or after YF vaccine; no data are available for live attenuated oral cholera vaccine (Vaxchora) given simultaneously with YF vaccine. [1]
- The label says that when vaccines are given concomitantly, use separate syringes at separate sites and do not combine or mix YF-VAX with any other vaccine; the vaccination center should complete, sign and stamp an International Certificate of Vaccination, and the immunization record should contain the date, lot number and manufacturer. [3]
Storage and handling
- Store at 2 to 8 °C (35 to 46 °F); do not freeze; do not use after the expiration date; YF-VAX does not contain a preservative. [3]
- For areas where cold-chain problems occur, the label states the half-life is reduced from approximately 14 days at 35 to 37 °C to 3 to 4.5 days at 45 to 47 °C; vial stoppers for the vaccine and diluent are not made with natural rubber latex. [3]
Contraindications and precautions
| Source | Contraindications | Precautions |
|---|---|---|
| CDC Yellow Book (Box 4.21.1) | Age younger than 6 months; allergy to vaccine component; symptomatic HIV infection or CD4 counts below 200/mL (or below 15% of total lymphocytes in children under 6 years); primary immunodeficiencies; immunosuppressive and immunomodulatory therapies; malignant neoplasms; thymus disorder associated with abnormal immune cell function; transplantation. [1] | Age 6 to 8 months; age 60 years or older; breastfeeding; asymptomatic HIV infection with CD4 counts 200 to 499/mL (or 15% to 24% of total lymphocytes in children under 6 years); pregnancy. [1] |
| FDA label (YF-VAX) | History of acute hypersensitivity to any component or to eggs or egg products (the virus is propagated in chicken embryos; less severe or localized egg or feather allergy is not a contraindication); infants less than 9 months of age (risk of encephalitis); lactating women providing breastmilk to infants less than 9 months of age; severe immunosuppression. [3] | The decision to vaccinate individuals 60 years of age and older and immunosuppressed individuals needs to weigh the risks and benefits of vaccination and the risk for exposure to yellow fever virus. [3] |
The Yellow Book (2026 edition) lists age younger than 6 months as the age contraindication and age 6 to 8 months as a precaution, whereas the FDA label posted for YF-VAX lists age younger than 9 months as a contraindication (and lactating women providing breastmilk to infants younger than 9 months); the Yellow Book also lists breastfeeding as a precaution rather than a contraindication. The two sources conflict on these points. [1] [3]
If considering vaccination in a person with an allergy to a vaccine component, desensitization can be performed under direct supervision of a physician experienced in the management of anaphylaxis, and a skin-test protocol is described in the label for suspected egg sensitivity. [1] [3]
Safety and adverse events
Reactions to YF vaccine are generally mild: 10% to 30% of vaccinees report mild systemic symptoms (headache, low-grade fever, myalgia) beginning within days and lasting 5 to 10 days; anaphylaxis is reported at a rate of 1.3 cases per 100,000 doses administered among U.S. travelers. [1]
Yellow fever vaccine-associated neurologic disease (YEL-AND) includes acute disseminated encephalomyelitis, Guillain-Barré syndrome, meningoencephalitis and rarely cranial nerve palsies; the incidence after YF-VAX in the United States is 0.8 per 100,000 doses overall and 2.2 per 100,000 doses in people aged 60 years or older, and almost all cases occur in first-time recipients (onset 2 to 56 days after vaccination). [1]
Yellow fever vaccine-associated viscerotropic disease (YEL-AVD) is a severe illness similar to wild-type YF disease with multiorgan dysfunction; it has been reported only after the first dose, the incidence after YF-VAX in the United States is 0.3 per 100,000 doses (1.2 per 100,000 in people aged 60 years or older), the median time to symptom onset is 4 days, and the case-fatality ratio is approximately 43%. [1]
The rate of reported serious adverse events after YF vaccination in people aged 60 years or older is 7.7 per 100,000 doses distributed, compared with 3.8 per 100,000 for all YF vaccine recipients. [1]
Syncope can occur following or even before vaccination, and procedures should be in place to prevent falling and injury; vaccinees should be instructed to report serious adverse events up to 30 days after vaccination. [3]
Special populations
Pregnancy: safety of YF vaccination in pregnancy has not been studied in large prospective trials; if possible pregnant women should avoid travel to YF risk areas, but if travel is unavoidable and the exposure risk outweighs the vaccination risk, vaccination is appropriate, otherwise offer a medical waiver; women vaccinated in pregnancy should receive an additional dose before they are at risk and no longer pregnant, and ACIP recommends waiting 4 weeks after vaccination before conceiving. [1]
Breastfeeding: at least 3 YEL-AND cases have been reported in exclusively breastfed infants younger than 1 month whose mothers were vaccinated; CDC says avoid vaccinating breastfeeding women until specific research data are available, but vaccination is recommended when a nursing woman cannot avoid or postpone travel to YF-endemic areas, and some experts recommend pumping and discarding milk for at least 2 weeks after vaccination. [1]
HIV: asymptomatic people living with HIV with CD4 counts of 200 to 499/mL had no serious adverse events in combined studies of more than 500, but have a reduced immunologic response; if there is no evidence of immune suppression (CD4 500/mL or more, or 25% or more of total lymphocytes in children under 6 years) YF vaccine can be administered, serologic testing is worth considering, and ACIP recommends boosters every 10 years if risk continues. [1]
Infants 6 to 8 months: two YEL-AND cases have been reported and ACIP recommends travel to YF-endemic countries be postponed or avoided whenever possible; older adults 60 years and over: carefully consider the risks and benefits of first-time vaccination because YEL-AVD has been reported exclusively, and YEL-AND almost exclusively, in primary vaccine recipients. [1]
Counseling pearls for the pharmacy counter
- Yellow fever vaccine is a live vaccine given as a single shot; one dose provides lifelong protection for most people. [2]
- Avoid mosquito bites in addition to vaccination: use insect repellent, wear long-sleeved shirts and long pants, and stay in well-screened or air-conditioned areas. [2]
- Vaccination certificates are valid commencing 10 days after vaccination; travelers should check destination entry requirements and keep the signed and stamped International Certificate of Vaccination. [3]
- If the decision is made not to vaccinate a traveler, provide a medical waiver, emphasize the critical importance of adhering to insect bite precautions, and discuss risks associated with being unvaccinated. [1]
Common patient questions
A 70-year-old first-time traveler is going to rural West Africa. Is YF vaccine given?
It is a precaution, not a contraindication: age 60 or older increases the risk of serious adverse events, so the risks and benefits should be weighed carefully and shared decision-making used; if the decision is not to vaccinate, provide a medical waiver and emphasize insect bite precautions. [1]
Does a person vaccinated 15 years ago need a booster?
Not for most people: CDC says a single dose is adequate for most travelers and the International Certificate is valid for life; a booster can be considered for travelers whose last dose was 10 or more years ago going to higher-risk settings. [1]
Can YF vaccine and MMR be given on the same day?
Coadministration is acceptable if necessary to ensure the traveler is vaccinated before travel, but whenever possible YF and MMR should be one month apart. [1]
A patient with egg allergy needs YF vaccine. What now?
The YF-VAX label contraindicates the vaccine in anyone with a history of acute hypersensitivity to eggs or egg products (less severe or localized egg allergy is not a contraindication) and describes a skin-test protocol for suspected egg sensitivity. [3]
Where can YF vaccine be given?
In the United States YF-VAX is supplied only to designated Yellow Fever Vaccination Centers authorized to issue certificates of yellow fever vaccination. [3]
References
- Centers for Disease Control and Prevention. Yellow fever. In: CDC Yellow Book: Health Information for International Travel, 2026 edition. Page dated April 23, 2025. Accessed October 12, 2026. https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/yellow-fever.html. Accessed October 12, 2026.
- Centers for Disease Control and Prevention. Yellow fever vaccine: what you need to know. Vaccine Information Statement, April 1, 2020. Accessed October 12, 2026. https://www.cdc.gov/vaccines/hcp/current-vis/yellow-fever.html. Accessed October 12, 2026.
- YF-VAX (yellow fever vaccine): package insert as posted on FDA's product page (older-format label; no revision date in the posted document). Sanofi Pasteur Inc. U.S. Food and Drug Administration. Accessed October 12, 2026. https://www.fda.gov/media/76015/download?attachment. Accessed October 12, 2026.
- U.S. Food and Drug Administration. YF-VAX product page (content current as of 05/23/2025). Accessed October 12, 2026. https://www.fda.gov/vaccines-blood-biologics/vaccines/yf-vax. Accessed October 12, 2026.
For professional education. Check current labeling and guidance before acting. Not medical advice.
