Seroprevalence of SARS-CoV-2 Antibodies in Employees of Three Hospitals of a Secondary Care Hospital Network in Germany and an Associated Fire Brigade: Results of a Repeated Cross-Sectional Surveillance Study Over 1 Year

Abstract

Healthcare workers (HCWs) are playing a vital role in the current SARS-CoV-2 pandemic. This study investigated how infection spreads within three local hospitals and an associated fire brigade in Germany by testing employees for the presence of SARS-CoV-2 IgG antibodies over one year. The three observational periods corresponded to the initial three pandemic waves: first wave: June–September 2020, second wave: October 2020–January 2021, and third wave: February–June 2021. We analysed 3285 serum samples of 1842 employees, which represents 65.7% of all employees. Altogether, 13.2% employees were seropositive: 194/1411 HCWs (13.7%) and 49/431 non-HCWs (11.4%) with a clear increase of seroprevalence from the first (1.1%) to the second (13.2%) and third (29.3%) pandemic wave. HCWs presumably had an additional occupational risk for infection in the second and third wave due to an increase of infection pressure with more COVID-19 patients treated, showing possible weak points in the recommended infection prevention strategy.

SARS-CoV-2 seroprevalence in workers from a Colombian University Hospital

“…In fact, these figures are like those estimated for the general population, which at that time was 33% for Colombia and 38% for India [ 12 , 13 ]. Moreover, these results are consistent with those reported by Hildebrandt et al [ 14 ] with 29% of seroprevalence among 714 health workers in Germany evaluated between February and June 2021.…”

Trajectories of Seroprevalence and Neutralizing Activity of Antibodies against SARS-CoV-2 in Southern Switzerland between July 2020 and July 2021: An Ongoing, Prospective Population-Based Cohort Study

“…We completed our third round more than six months after the commencement of the stepwise vaccination campaign in Switzerland, and we used a high-quality serological testing method of the acquired immune response. We found increases in seroprevalence over time that are consistent in magnitude with evidence from studies that used repeated cross-sectional designs [ 9 , 55 , 56 ]. Our findings on the marked variation in the proportion of seroprevalence due to vaccination coverage are based on data collected before the spread of both the Omicron variant and the ensuing rapid increases in hybrid immunity in populations (whereby both vaccines and infection induced antibodies).…”

Non-Pharmacological Preventive Measures Had an Impact on COVID-19 in Healthcare Workers before the Vaccination Effect: A Cohort Study

“…This higher community incidence, contrasting with the lower incidence among healthcare workers, further underlines the important role played by non-pharmaceutical preventive measures at PSMar. Moreover, the opposite trend is observed in similar hospitals in Poland [ 24 ] and Germany [ 25 ], which show a significant increase in the incidence among healthcare workers, concluding that their preventive strategy should be improved. However, it should also be noted that the lower number of admissions of patients with COVID-19 in the second period compared to the first may have also contributed to the lower incidence of cases among healthcare workers.…”