SARS-CoV-2 Neutralizing Antibody has Better Diagnostic Sensitivity than IgM and IgG

COVID-19 has spread worldwide. However, SARS-CoV-2 serological markers, which usually important indicators of disease progression, remains to be studied. To determine serological patterns during infection and their corresponding influencing factors, we conducted a cohort study including 115 patients with COVID-19 from 41 hospitals. The study included measuring IgM, IgG, and neutralizing antibodies (NAb) in serum, conducting epidemiological survey of the subjects, and retrieving clinical indicators from electronic medical records. We found NAb had the highest seroconversion rate (79.61%), followed by IgG (60.42%), and IgM (26.56%). Seroconversion rate peaked 20–40 d post-infection with NAb reaching 100%. The Geometric mean of NAb ID 50 is 201 (30 to 6271). The NAb titer was positively correlated with duration of infection (p = 0), IgM (p = 0.016), and IgG (p = 0). Compared with IgM or IgG, NAb has better diagnostic sensitivity and serological patterns are valuable for clinical diagnosis and disease monitoring.