Highlights of the Trial
The study provides critical evidence regarding the minimum effective dose of the yellow fever vaccine in pediatric populations. Key highlights include:
- A low-dose (500 IU) regimen of the 17D-204 yellow fever vaccine failed to meet the -10% non-inferiority margin for seroconversion compared to the standard dose in infants aged 9–12 months.
- The seroconversion rate was 93% for the 500 IU dose versus 99% for the standard dose, representing a significant clinical gap in immunogenicity.
- Safety outcomes were comparable between the groups, with no serious adverse events attributed to the vaccination.
- Current WHO recommendations for fractional dosing in outbreak settings should not be extended to routine infant immunization programs.
