Symptoms and immunoglobulin development in hospital staff exposed to a SARS-CoV-2 outbreak.

Brandstetter, Susanne; Roth, Samra; Harner, Susanne; Buntrock-Döpke, Heike; Toncheva, Antoaneta; Borchers, Natascha; Gruber, Rudolf; Ambrosch, Andreas; Kabesch, Michael

BACKGROUND Worldwide, the number of SARS-CoV-2 infections is increasing. Serological immunoglobulin tests may help to better understand the development of immune mechanisms against SARS-CoV-2 in COVID-19 cases and exposed but asymptomatic individuals. The aim of this study was to investigate exposure to SARS-CoV-2, symptoms and antibody responses in a large sample of health care workers following a COVID-19 outbreak. METHODS A COVID-19 outbreak among staff members of a major German children's and women's hospital was followed by massive RT-PCR SARS-CoV-2 tests and provided the opportunity to study symptoms, chains of infection and SARS-CoV-2 specific antibody responses (IgG and IgA) by ELISA. Study participants were classified as COVID-19 cases, and persons with close, moderate or no exposure to SARS-CoV-2 in the clinical setting, respectively. RESULTS Out of 201 study participants, 31 were COVID-19 cases. While most study participants experienced many symptoms indicative for SARS-CoV-2 infection, anosmia and coughing were remarkably more frequent in COVID-19 cases. Approximately 80% of COVID-19 cases developed some specific antibody response (IgA and IgG) approximately 3 weeks after onset of symptoms. Subjects in the non COVID-19 groups had also elevated IgG (1.8%) and IgA values (7.6%) irrespective of contact history with cases. CONCLUSION We found that a significant number of diseased did not develop relevant antibody responses three weeks after symptom onset. Our data also suggests that exposure to COVID-19 positive co-workers in a hospital setting is not leading to the development of measurable immune responses in a significant proportion of asymptomatic contact-persons.