Yellow Fever Vaccine and Sexual Transmission Risk
Based on available evidence, there is no documented risk of transmission of the yellow fever vaccine virus to sexual partners through sexual contact. The Advisory Committee on Immunization Practices (ACIP) guidelines do not identify sexual transmission as a concern for yellow fever vaccine recipients 1.
Transmission Routes of Yellow Fever Vaccine Virus
The yellow fever vaccine contains a live attenuated virus (17D strain), and while the virus can replicate in the body, transmission to others is extremely limited and has only been documented in specific scenarios:
Documented transmission routes:
- Blood products: Transfusion-related transmission has been documented in three persons who received blood products collected from individuals vaccinated 4 days before donation 1
- Breastfeeding: There have been cases of transmission to breastfed infants, with one confirmed and one probable case of Yellow Fever Vaccine-Associated Neurotropic Disease (YEL-AND) reported in exclusively breastfed infants whose mothers were vaccinated 1
No evidence for sexual transmission:
- Despite extensive surveillance and reporting of adverse events related to yellow fever vaccine, there are no documented cases of sexual transmission in the ACIP guidelines or other research evidence 1
Vaccine Virus Replication and Viremia
After vaccination, recipients typically experience:
- Low-level viremia (virus in bloodstream) within 3-7 days post-vaccination
- Viremia typically persists for only 1-3 days
- Viremia resolves as YF-specific antibodies develop 1
This limited period of viremia and rapid clearance of the vaccine virus likely explains why sexual transmission has not been documented as a concern.
Precautions for Special Populations
While sexual transmission is not identified as a risk, the ACIP guidelines do highlight other important precautions:
- Pregnancy: Vaccination during pregnancy should be avoided unless travel to endemic areas is unavoidable 1
- Breastfeeding mothers: Vaccination should ideally be avoided due to the theoretical risk of transmission to infants through breast milk 1
- Immunocompromised individuals: Should not receive the vaccine due to risk of serious adverse events 1
Serious Adverse Events Associated with Yellow Fever Vaccine
While not related to sexual transmission, it's important to note that rare but serious adverse events can occur with the vaccine:
- Yellow Fever Vaccine-Associated Viscerotropic Disease (YEL-AVD): A severe, often fatal condition that mimics wild-type yellow fever infection 1, 2
- Yellow Fever Vaccine-Associated Neurotropic Disease (YEL-AND): Can cause neurological complications 1, 2
Conclusion
There is no evidence supporting sexual transmission of yellow fever vaccine virus to partners. The primary documented routes of transmission are through blood products and potentially through breast milk. The vaccine virus produces a brief, self-limited viremia that is quickly cleared as immunity develops.
For travelers to yellow fever endemic areas, the benefits of vaccination significantly outweigh the theoretical risk of transmission to sexual partners, which has not been documented in the literature.