[The prevalence rate of anti-SARS-CoV-2-IgG is 1.2% - Screening in asymptomatic outpatients in Germany (Northrhine-Westfalia)]

Abstract

Patients with newly diagnosed COVID-19 (coronavirus disease 2019) develop antibodies against SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). To date, few data have been obtained of the prevalence of SARS-CoV-2-antibodies in general population and in asymptomatic outpatients in Germany.From March 26 to June 4 2020, 415 asymptomatic outpatients were tested prospectively in Northrhine-Westfalia (Germany), to detect SARS-CoV-2-IgG-antibodies. In case of a positive result, anti-SARS-CoV-2-IgA was determined additionally.5 of 415 asymptomatic outpatients had positive SARS-CoV-2-IgG-antibodies with a calculated prevalence of 1.2%. Reference range of anti-SARS-CoV-2-IgA and IgG was defined as ratio for negative < 0.8, borderline 0.8-1.1 and > 1.1 positive. The mean concentration of SARS-CoV-2-IgG-antibodies of the positive 5 outpatients was lower than in symptomatic patients with COVID-19 (n = 12) and positive PCR of SARS-CoV-2 (3.04 ± 2.58 versus 8.05 ± 6.70; p = 0.002). 4 of 5 patients had elevated SARS-CoV-2-IgA-antibodies (1.61 ± 0.82). In 408 screening-outpatients with negative anti-SARS-CoV-2-ELISA-IgG (< 0.8), the mean ratio was 0.25 ± 0.13. Two patients were in the borderline range (0.83 and 0.86).The prevalence of 1.2% of SARS-CoV-2-IgG-antibodies and consequently the rate of infection in asymptomatic outpatients in Northrhine-Westfalia (Germany) is low. The impact of virus neutralisation by antibodies and consequently immunization is the challenge of further investigations.

Keywords: IgG-antibodies; SARS-CoV-2; prevalence; screening.