Low-Dose Yellow Fever Vaccine in Adults in Africa

In a randomized, noninferiority trial conducted in Uganda and Kenya, adults received either a standard dose or one of three lower doses (1000 IU, 500 IU, 250 IU) of the 17D-204 yellow fever vaccine. The study showed that doses of 500 IU and 1000 IU were noninferior to the standard dose in inducing seroconversion by day 28. The 250 IU dose narrowly met noninferiority in intention-to-treat analysis but not in per-protocol analysis. The trial supports the use of fractional doses in emergencies with vaccine shortages.

In a randomized, noninferiority trial conducted in Uganda and Kenya, adults received either a standard dose or one of three lower doses (1000 IU, 500 IU, 250 IU) of the 17D-204 yellow fever vaccine. The study showed that doses of 500 IU and 1000 IU were noninferior to the standard dose in inducing seroconversion by day 28. The 250 IU dose narrowly met noninferiority in intention-to-treat analysis but not in per-protocol analysis. The trial supports the use of fractional doses in emergencies with vaccine shortages.