This study has been designed to assess the feasibility of screening asymptomatic workers and to investigate the extent of infection, as determined by pharyngeal swaps analysis and immune response against the virus and virus specific CD4+ and CD8+ T-cell analysis. Furthermore, the extent to which virus-specific CD4+ and CD8+ T-cells are induced is investigated as well as the persistence of virus-specific memory CD4+ and CD8+ T-cells -especially in asymptomatic infected persons.

In total, approximately up to 500 workers will be enrolled into the trial to have 450 evaluable subjects at the end of the study. There will be three individual cohorts of workers working in different departments: workers from the production area (cohort 1), workers from the laboratory area (cohort 2) and workers working in other areas (cohort 3).

The fraction of asymptomatic or subclinical infections should be determined as well as the kinetics of the immune responses. For each timepoint the difference between the cohorts is investigated. This study also aims to evaluate the impact of sanitary and preventive measures taken within the company during the pandemic situation.

Epidemiological exposure data and biological samples will be systematically collected. The present study is being conducted in line with World Health Organization recommendations to help understanding the epidemiology of SARS-Cov-2.