Prospective Longitudinal Serosurvey of Healthcare Workers in the First Wave of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Pandemic in a Quaternary Care Hospital in Munich, Germany

Abstract

Background High infection rates among health care personnel in an uncontained pandemic can paralyze health systems due to staff shortages. Risk constellations and rates of seroconversion for health care workers during the first wave of the SARS-CoV-2 pandemic are still largely unclear. Methods Health care personnel (n=300) on different organizational units in the LMU Munich University Hospital were included and followed in this prospective longitudinal study in the period of March 24 until July 7, 2020. Participants were monitored in intervals of two to six weeks using different antibody assays for serological testing and questionnaires to evaluate risk contacts. In a subgroup of infected participants, we obtained nasopharyngeal swabs to perform whole genome sequencing for outbreak characterization. Results Health care workers involved in patient care on dedicated COVID-19 wards or on regular non-COVID-19 wards showed a higher rate of SARS-CoV-2 seroconversion compared to staff in the emergency department and non-frontline personnel. The landscape of risk contacts in these units was dynamic, with a decrease of unprotected risk contacts in the emergency department and an increase on non-COVID-19 wards. Both, the intensity and number of risk contacts, were associated with higher rates of seroconversion. On regular wards, staff infections tended to occur in clusters, while infections on COVID-19 wards were less frequent and apparently independent of each other. Conclusion The risk of SARS-CoV-2 infection for front-line health care workers was increased during the first pandemic wave in Southern Germany. Stringent measures for infection control are essential to protect all patient-facing staff during the ongoing pandemic.

In-depth profiling of COVID-19 risk factors and preventive measures in healthcare workers

“…High-risk exposures in hospitals can be minimized by strictly enforcing patients and staff to wear appropriate personal protective equipment (PPE), testing patients for acute SARS-CoV-2 infection upon admission and rapid isolation of suspected COVID-19 cases in separate rooms. In the hospital complex surveyed here, the ER implemented these measures early on, possibly explaining the low seropositivity among these HCWs, despite the ER being a common entry point for symptomatic COVID-19 patients into hospitals [ 34 ].…”

Assessment of SARS-CoV-2 Infection among Healthcare Workers of a German COVID-19 Treatment Center

“…In a large hospital in Spain, cumulative prevalence of SARS-CoV-2 infection was reported with 11.2%, yet neither the professional category nor daily patient contact or working in COVID-19 units was identified as a risk factor for infection [ 37 ]. However, some hospitals indeed reported a higher SARS-CoV-2 prevalence for example in housekeeping staff or employees with high exposure to (COVID-19) patients [ 8 , 11 , 38 , 39 ]. For example, a study conducted in more than 3000 employees of a large health care provider in Sweden and Denmark identified the number of patient contacts during a workday as the most prominent predictor for seropositivity (2.8% in Denmark and 8.3% in Sweden).…”

“…In addition, Weinberger et al reported that HCW on both COVID-19 and regular non-COVID-19 wards had a greater rate of seroconversion than non-frontline personnel. Moreover, both the intensity and number of risk contacts were associated with seropositivity in their study [ 8 ].…”

“…In this context, healthcare systems and especially public and private hospitals play a particular role: healthcare workers (HCW) are at the frontline, in daily contact with COVID-19 patients and are therefore potentially at a higher risk than the global population [ 6 , 7 , 8 ]. New hygiene regulations and standards based on the WHO guidelines were adopted by the German federal government and local authorities to prevent patient-to-HCW transmission.…”

“…Only in autumn 2020 did FFP2 masks become gradually available in our hospital for all employees. However, data on whether employees with a high level of exposure to COVID-19 patients might be at a greater risk of infection despite the usage of PPE are controversial [ 8 , 11 , 12 , 13 ]. Moreover, the role of housekeeping and transport staff with high mobility within the hospital as a potential vector of SARS-CoV-2 transmission remains poorly investigated.…”