SARS-Cov-2 IgG positive rates were comparable among mild, moderate and severe COVID-19 patients
The novel coronavirus nucleic acid test of 56 cases of patients was negative. The SARS-Cov-2 IgM titer was average 0.39 (0.19-0.65) , the SARS-Cov-2 IgM titer among mild, moderate and severe patients were incomparable ( P = 0.644, Table 2 ) . The positive rate of SARS-Cov-2 IgM titer in severe group was higer than others, while incomparable ( P = 0.266, Table 2 ) in the three groups. The SARS-Cov-2 IgG titer was average 0.72 ( 0.84-17.50 ) , the SARS-Cov-2 IgG titer among mild, moderate and severe patients were incomparable ( P = 0.079, Table 2 ) . The positive rate of SARS-Cov-2 IgG titer within 6 to 9 months after discharge is 73.2%, while the positive rate of SARS-Cov-2 IgG titer was comparable ( P = 0.01, Table 2 ) in the mild and moderate groups. Comparing the data of the three groups of patients, we found that the IgG level of the moderate and severe groups was significantly higher than that of the mild group ( Table 2 ) . Thus, SARS-Cov-2 IgG positive rates were comparable among mild, moderate and severe COVID-19 patients during 6-9 months follow-up.