A. Anti-Spike (S) IgG (ng/mL) responses raised in sera from participants receiving two doses of LNP-saRNA in the dose-ranging cohort (1 μg, 1 μg in green and 10 μg, 10 μg in orange) and the expanded safety cohort (1 μg, 10 μg in pink). Responses are shown on the day of second vaccination, and at 2 and 4 weeks after second vaccination. Baseline convalescent sera depicted in black. B. Pseudoneutralising antibodies IC50 from participants receiving two doses of LNP-saRNA in the dose-ranging cohort (1 μg, 1 μg in green and 10 μg, 10 μg in orange) and the expanded safety cohort (1 μg, 10 μg in pink). Responses are shown at 2 and 4 weeks after second vaccination. Baseline convalescent sera depicted in black. Error bars detail the median and interquartile range amongst responders. Responses that did not meet criteria for a positive response are shown on the bottom row with numbers of participants <LOQ (limit of quantification).