Seroconversion panels demonstrate anti-SARS-CoV-2 antibody development after administration of the mRNA-1273 vaccine

•Two seroconversion panels from samples before and after vaccination with mRNA-1273 vaccine.•Subjects positive for IgG prior to vaccination had a higher response to the first vaccination.•Responses to the first dose of vaccine were lower in naïve elderly subjects.•All subjects had positive responses after the second vaccine dose.•Seropositive or convalescent subjects may be sufficiently protected after one dose of vaccine.