BERNA-YF (Flavimun) is a live, attenuated yellow fever (YF) vaccine of the 17D strain produced by Berna Biotech Ltd. following a transfer of technology from the Robert Koch Institute (RKI) in Berlin, Germany. In this phase 3 bridging study, the immunogenicity and safety of BERNA-YF were compared with the original RKI YF vaccine (RKI-YF) and to a current, commercially available YF vaccine, Stamaril (AP-YF; Aventis Pasteur, Lyon, France), in 304 healthy, adult volunteers. All three vaccines elicited an effective immune response with seroprotection achieved in 100% of individuals in each vaccine group at a neutralizing antibody titer 1: 10. BERNA-YF was shown to be comparable to the other two vaccine products, and subgroup analysis showed no differences in immune response between three consecutive production batches. The immune response to BERNA-YF and RKI-YF was very similar, with no significant difference in antibody titer between the two groups (P 0.4634). However, AP-YF vaccination resulted in a significantly lower antibody titer (P< 0.0001 versus BERNA-YF). Males exhibited a higher antibody response than females to both BERNA-YF and RKI-YF, but not to AP-YF. All three vaccines were well tolerated and no serious adverse events were reported.