The evaluation of the relationship between antibody response and COVID-19 disease severity

Abstract

Background: World Health Organization (WHO) reported COVID-19 as a pandemic, on March 11th, 2020. The quick and accurate diagnosis is crucial to provide the appropriate treatment and isolation process. Immunity against COVID-19 is essential for disease control. There is scant information about antibody response and disease severity. In this study, we aimed to investigate the relationship between clinical severity and COVID antibody response. Methods: Hospitalized PCR (n=10) and/or radiologically (n=31) proven 35 COVID-19 patients were included in the study. The blood samples were collected at least eight days after the onset of symptoms and studied by using the COVID-19 IgG/IgM Rapid Test. Patients were divided as mild (n= 14), severe (n=12) and critical (n=9) according to COVID-19 disease severity. The results were compared among the groups. Results: A total of 35 COVID-19 patients’ (mean age: 54.65±16.51 years, Male/Female: 23/12) rapid test results were compared according to clinical severity. A significant correlation was observed between disease severity and IgG results in both PCR positive (p=0.007) and whole patients (p=0.026). The positive IgG ratio was significantly low in the mild patient group while it was higher in severe and critical patients. Conclusions: Our study reveals that the greater antibody response occurs with the more serious COVID-19 disease. The application of the rapid test, in addition to PCR, may be used as a clue to foresee the clinical progression. These tests not only have an important role in diagnosis with PCR tests but also are associated with disease severity.