[SARS-CoV-2 antibodies in ICU and clinic staff : From Germany's region with the highest infection rate].

Background: Healthcare workers are a high-risk population for SARS-CoV‑2 infection. For capacity planning of healthcare providers and to optimize protection of healthcare workers (HCW) in SARS-CoV‑2 pandemics, it is essential to know the risk of infection and potential immunity status of staff dealing with COVID-19 patients.
Materials and Methods: We examined seropravalence of SARS-CoV‑2 IgM/IgG antibodies (AB) in HCW of a region with the highest rate of infection (1570/100,000) during COVID-19 pandemic in Germany, 4 months after its start. Employees of a nonmedical company (MU) served as control group. Demographic data, medical history and working situation were recorded.
Results: A total of 1838 HCW and 986 MU volunteered to participate. Seroprevalence for SARS-CoV‑2 in HCW was 15.1% and 3.7% in MU. Among HCWs, nurses had a seropositivity of 20.0%, ICU personnel 20.3%, housekeepers 19.3%, physicians 12.0%, medical services (e.g., radiology, physiotherapy) 11.3%, administration 7.1% and technical services 6%. Symptoms typical for COVID-19 were not experienced by 10% of seropositive HCWs.
Conclusion: Seroprevalence of SARS-CoV‑2 antibodies in HCW of a region heavily affected by COVID-19 is with 15.1% significantly higher than in a control group of nonmedical staff with 3.7%. Infection rate in HCW was higher in staff with close contact to infected patients. Seropositivity in ICU personnel is higher than in other clinical professions. The occupational risk for housekeepers seems to be underestimated.