Figure 3.

Detection of SARS-CoV-2-specific IgG and IgM antibodies with indirect immunity-based kit produced by manufacturer B. (A) Density of SARS-CoV-2-specific IgG antibody detection. Before testing, 20 samples were heat-inactivated at 56°C for 30 min, 56°C for 45 min, or 60°C for 30 min, respectively. (B) COI values for SARS-CoV-2-specific IgM antibody. Before testing, 20 samples were heat-inactivated at 56°C for 30 min, 56°C for 45 min, or 60°C for 30 min. The detection of SARS-CoV-2 antibody without heat-inactivation were used as control. *p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001.