COVID-19 Study to Assess Immunogenicity, Safety, and Tolerability of Moderna mRNA-1273 Vaccine Administered With Casirivimab+Imdevimab in Healthy Adult Volunteers

The primary objectives of the study are: * To evaluate the extent of effect, if any, of REGN10933+REGN10987 administration on vaccine-induced neutralizing antibody responses to SARS-CoV-2 by Moderna mRNA-1273 * To evaluate the time interval required between REGN10933+REGN10987 administration and Moderna mRNA-1273 vaccination, to ensure no meaningful impact on vaccine-induced neutralizing antibody responses to SARS-CoV-2 The secondary objectives of the study are: * To quantify the alteration of antigen specificity of vaccine-induced SARS-CoV-2 antibody responses when administered with different dose regimens of REGN10933+REGN10987 * To evaluate the safety and tolerability of REGN10933+REGN10987 and Moderna mRNA-1273 vaccine when administered in close succession * To assess the concentrations of REGN10933 and REGN10987 in serum over time in participants who receive REGN10933+REGN10987 and Moderna mRNA-1273 vaccine * To evaluate the immunogenicity of REGN10933 and REGN10987 over time