Nine cases of sars-cov-2-pcr-positive samples showed no increase of antibodies against sars-cov-2

Abstract

Background/Aim: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been affecting Hokkaido, Japan since late February 2020 until present. The aim of this study was to report the relationship between anti- SARS-CoV-2 antibody-positive and SARS-CoV-2 PCRpositive cases by analyzing anti-SARS-CoV-2 antibodies (IgG and total-Ig). Patients and Methods: Serum samples were collected from care workers and nurses in two nursing homes and two hospitals which underwent virus outbreak. All people were confirmed to be SARS-CoV-2-positive by RTqPCR and their sera was analyzed for anti-SARS-CoV-2 antibodies (IgG and total-Ig). Results: Although 34 out of 43 samples (79.1%) showed enough amount of anti-SARS-CoV- 2 antibodies, 9 RT-qPCR -positive samples (20.9%) showed absence of anti-SARS-CoV-2 antibodies in their sera. Conclusion: The results that 20.9% of RT-qPCR-positive samples with SARS-CoV-2 showed absence of anti-SARSCoV- 2 antibodies provides a possibility that the innate immune reaction could eliminate the virus without activating adaptive immune reaction.