Retrospective analysis of persons after mild COVID-19 in the context of a convalescent plasma donation

Objective About a year ago, the first reports from China about the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), were received. At that time, it was not yet foreseeable that this virus would cause a worldwide pandemic. The aim of our study was to characterize persons who had a mild COVID-19 course and to determine the antibody status of the individuals, since most publications focus on patients who need hospitalization.

Material and Methods We have obtained convalescent plasma from individuals in our region after recovery from COVID-19 and included these individuals in our study. From 615 persons who thought they were infected with SARS-CoV-2, we were able to identify 426 who were most likely infected with SARS-CoV-2. We determined this based on the detection of antibodies against SARS-CoV-2 and on virus detection by RT-PCR during the disease.

Results The most common symptoms were fatigue, cough and olfactory and gustatory dysfunction. The median duration of the disease was 12 days (interquartile range: 7-17 In 82.4% of the persons, anti-SARS-CoV-2 IgG was detected, additionally IgA antibodies were found in 73.9% of the persons. Despite a positive RT-PCR result during the disease in 10.8% of our cohort, no antibodies were detectable. Nevertheless, of 24 persons with asymptomatic courses of COVID-19, antibodies against SARS-CoV-2 could be detected in 23 (96%). We also found a correlation between disease duration and IgG antibody detection.

Conclusion In this study, we were able to describe the course and antibody status of mild COVID-19. As already described in the literature, we were able to show that not all persons after recovery from COVID-19 also produced antibodies against SARS-CoV-2 or that these were not detectable. On the other hand, antibodies could be detected in almost all asymptomatic cases. How important the antibodies are for the protection against a new infection with SARS-CoV-2 has to be investigated in further studies. In addition, the role of the cellular immune response with regard to prolonged immunity has to be investigated.

Publication History

Article published online:
18 June 2021