Immunologic Response
In the vaccine group, the seroconversion rates of anti–SARS-CoV-2 S1 IgG increased 4 weeks after the second (81.1% [95% CI, 79.7%-82.2%]) and third (92.9% [95% CI, 91.4%-94.2%]) doses (A specific IFN-γ response to SARS-CoV-2 S1 was analyzed in 363 participants 4 weeks after the second dose (295 from the vaccine group and 68 from the placebo group). The geometric mean titer ratio of IFN-γ between the vaccine and placebo groups was 5.3 (95% CI, 3.1-9.2; 