Participants were given a single IM injection of the vaccine of the placebo in the arm and monitored 30 minutes post injection for ADRs. Follow ups on the patients were performed, 14 days, 28 days and 6 months post vaccination for measuring specific antibody responses, neutralizing antibody responses, and other safety and immunogenicity assessments. Patients were to self report ADEs experienced post vaccination over the course of the study for documentation. To measure the specific antibody response blood samples were taken the day of and 14 and 28 days post vaccination and responses against the receptor binding domain were measured with ELISA kits. Neutralizing antibody and cellular immune responses were measured before vaccination and 28 days after. The cell immune response was measured with ELISpot assays of interferon γ and the neutralization antibody response was measured with a serum neutralization assay.