Seropositivity of COVID-19 asymptomatic nurses using Anti-SARS-CoV-2 nucleocapsid antibodies

Background: Anti-SARS-CoV-2 antibodies in symptomatic and asymptomatic cases provides helpful insight about its clinical implications. Aims and Objectives: The aim of this study is to determine anti-nucleocapsid IgG antibodies in nurses, qualitatively, both in asymptomatic and symptomatic nurses, and to determine the rate of asymptomatic cases. Second, to compare antibody reactivity from asymptomatic and symptomatic subjects. Materials and Methods: Samples were collected from four hospitals in the Southern Region, Najran, Kingdom of Saudi Arabia (KSA). Quantitative enzyme-linked immunosorbent assay from Epitope Diagnostic, Inc were used to measure the level of anti-nucleocapsid (anti-NC) antibodies in nurses. Results: One hundred twelve samples tested positive for antibodies (70%). Other variables were assessed, including age, gender, ABO blood group, and nationality. A significant difference was found between asymptomatic nurses vs. those with negative antibodies (*P = 0.0147), suggesting they could have transmitted SARS-CoV-2 unknowingly. Forty-one nurses (25.6%) were symptomatic, while 99 nurses were asymptomatic (61.8%). Conclusion: In this study, 112 nurses (70%) tested positive for the anti-NC antibodies, 41 (25.6%) were symptomatic, 99 (61.8%) were asymptomatic, and 48 (30%) were anti-NC antibody negative. Future work should focus on the association of respiratory disease with the concentration of antibodies, and if antibodies wane rapidly after COVID-19 infection.