Fig. 1: ACT-BOOSTER clinical study design.

71 healthy subjects 18–64 years of age were enrolled in this ACT-Booster study who had completed dosing regimens of a regulatory-approved/-authorized vaccination at least 3 months prior to enrollment (median days, 300 days; range, 113–399 days). Each subject received a single s.c. booster dose of 90 µg of non-adjuvanted AKS-452 and assessed for immunogenicity and safety on days 28, 56, 90, 180, and 273. One subject was lost to follow-up prior to the day-56 visit and therefore was excluded from immunogenicity analyses.