There are few studies to compare antibody response against anti-spike (S) and anti- nucleoprotein (N) SARS-CoV-2.
The aim of this study was to evaluate the IgG antibody production against S and N antigens of the virus and their correlation with the time and severity of the disease.
The IgG antibodies against S and N antigens of SARS-CoV-2 in serum specimens of 72 symptomatic patients who tested real-time reverse transcription polymerase chain reaction positive for SARS-CoV-2 were detected using the ELISA technique. Different antibody response was compared and the correlation with the time from disease onset and the severity was evaluated.
Forty-eight of 72 (67%) patients tested positive for anti-SARS-CoV-2 antibodies, while 24 (33%) did not have detectable antibodies. Comparison of antibody levels for N and S antibodies showed that they correlate with each other well (
Nearly one-third of the confirmed COVID-19 patients had negative serology results. Lower percent positivity at early time points after symptom onset (less than 1 week) was seen using anti-S SARS-COV-2 IgG kit compare to the anti-N SARS-CoV-2 IgG; therefore, clinicians should interpret negative serology results of especially anti-S SARS-CoV-2 IgG with caution.