Licensed vaccine product
YF-VAX: side effects, ingredients & package insert
Sanofi Pasteur · yellow fever vaccine · live attenuated · subcutaneous · 0.5 mL
YF-VAX ingredients (FDA package insert, Section 11)
Per-dose composition as stated in the prescribing information; verified 2026-07-09. Click an ingredient for every vaccine that contains it.
| Role | Ingredient | Amount per dose |
|---|---|---|
| Antigen | Yellow fever virus (live, attenuated) | ≥4.74 log10 PFU per 0.5 mL |
| Preservative | None (preservative-free) | No preservative added. |
| stabilizer | Sorbitol | stabilizer (label quantity) |
| stabilizer | Gelatin | stabilizer (label quantity) |
| culture_medium_residual | Egg protein | residual from chick embryo culture |
Source: FDA package insert. Formulations change — re-verify before clinical use.
YF-VAX side effects: where the data is
Reported reactions for YF-VAX and the other yellow fever products are compiled on the yellow fever vaccine page: pre-licensure trial reactogenicity, VAERS report counts, and international databases (Canada Vigilance, EudraVigilance, Lareb, VigiAccess). Those counts are spontaneous reports with no denominator — a report does not establish that the vaccine caused the event.
YF-VAX lot number lookup
This site does not yet hold lot-level VAERS counts for yellow fever vaccines. Any lot can still be searched in the lot explorer; a lot number is printed on the vaccination record and the vial.
Schedule and age range
Licensed ages and the recommended series for yellow fever vaccines are on the yellow fever vaccine page; how 31 countries schedule it is on yellow fever schedule by country. Always confirm the product-specific age range in the current package insert.
Common questions about YF-VAX
What are the side effects of YF-VAX?
Common reactions listed in the YF-VAX package insert are injection-site pain, redness or swelling and short-lived systemic symptoms such as fever, tiredness or irritability. Rarer events and the reported counts from VAERS and international databases are on the yellow fever vaccine page; counts are reports, not rates, and do not prove the vaccine caused the event.
What is in YF-VAX?
YF-VAX contains Yellow fever virus (live, attenuated) as antigen; adjuvant: none; it is preservative-free. Excipients: Sorbitol, Gelatin, Egg protein. Amounts per dose are in the table above, taken from Section 11 of the FDA package insert (verified 2026-07-09).
Where is the YF-VAX package insert?
The FDA-licensed prescribing information for YF-VAX is published by Sanofi Pasteur and the FDA; the source used for this page is https://www.fda.gov/media/76015/download. Formulations change, so re-verify the current insert before clinical use.
Reviewed 2026-10-08 · Matthew Thomas J Halma, Founder, Open Source Medicine Foundation. Informational, not medical advice.