Context: On March 11, the World Health Organization (WHO) announced the current corona virus disease 2019 (COVID-19) outbreak as a pandemic. The first laboratory-confirmed case of COVID-19 in Austria was announced on February 27, 2020. Since then, the incidence of infection follows a gradual increase. Measurements taken by the Austrian government include travel restrictions, closing of national borders, social distancing, a mandatory use of facemasks in public, and closing of stores and restaurants. The underlying aim of those imposed restrictions is to contain the viral transmission and to slow spreading of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Objectives: The aims of this study are to determine i) how many employees in Austrian trauma hospitals and rehabilitation facilities have virus specific IgG and IgM antibodies against SARS-CoV-2, ii) how many are active virus carriers (symptomatic and asymptomatic), iii) how many employees are in their incubation period during the study period, and iv) to calculate the SARS-CoV-2 prevalence together with a specific occupation associated infection risk within the different specifications of health care workers.

Study Design: Open uncontrolled observational cross-sectional study.

Setting/Participants: A total of 4000 employees in 11 Austrian trauma hospitals and rehabilitation facilities of the Austrian Social Insurance for Occupational Risks (AUVA) will be invited to participate in the study.

Study Interventions and Measures: An antibody test for SARS-CoV-2 specific IgG and IgM antibodies, and a RT-PCR test based on oropharyngeal swab samples, as well as laboratory-based antibody tests using ELISA, will be implemented to ensure protection and preservation of health in hospital staff and are not part of the study. The tests will be conducted twice, with approximately two weeks in between testing. The results of the tests will be used for statistical analysis in this study together with a questionnaire including questions related to personal health, traveling activities, living situation, as well as inquiries of symptoms and comorbidities.

Inclusion Criteria:

• employees in Austrian trauma hospitals and rehabilitation facilities of the Austrian Social Insurance for Occupational Risks (AUVA)

Exclusion Criteria:

• NA

All employees in Austrian trauma hospitals and rehabilitation facilities of the Austrian Social Insurance for Occupational Risks (AUVA) will be invited to participate in the study. In total, 4000 individuals in 12 hospitals and rehabilitation facilities in Austria will participate in the study.

IPD will be encrypted and anonymised.