Fig. 1.

Immunization of hamsters with saRNA and challenge by direct contact exposure to infected animals. (a) Schematic of immunization and challenge schedule. Groups of n = 6 animals were immunized by I.M. administration with two doses, given 4 weeks apart, of saRNA encoding influenza HA (control group) of SARS-CoV-2 S. Two weeks after the second dose, immunized hamsters were cohoused with infected donor hamsters one day after they had been intranasally inoculated with 10³ pfu SARS-CoV-2 either WT (D614G) variant (B.1.238) or Alpha VOC (B.1.1.7). (b)SARS-CoV-2 S specific IgG antibody levels in sera of naïve or immunized hamsters after first and second dose of saRNA vaccine measured by ELISA. p value established using a paired student’s t test. (c)Neutralizing antibody levels in sera of immunized hamsters collected 2 weeks after second dose of saRNA vaccine measured using a lentivirus pseudotype neutralization assay.