In a recent study posted to the medRxiv* preprint server, researchers conducted an observational study to assess severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence and infection status among Jena University Hospital (JUH) employees.
JUH is the only hospital in the state of Jena in central Germany, with a population of ~111,000. In March 2020, the authorities mandated masking for all JUH staff members, including (HCWs) and administration staff, to reduce nosocomial SARS-CoV-2 transmissions. Additionally, they prohibited the staff members from attending conferences or training activities outside JUH. From February 2021, SARS-CoV-2 vaccination was made available to all staff members. Subsequently, by December 2021, 94% of physicians, 88% of nurses, and 85% of administration staff had received COVID-19 vaccines. Even before vaccination, SARS-CoV-2 seroprevalence was low among the JUH staff members (2.7%).
HCWs take adequate infection control measures, like they use personal protection equipment (PPE), maintaining hand hygiene, and physical distancing in healthcare settings, which helps reduce nosocomial SARS-CoV-2 transmissions. Vaccination of patients and HCWs further reduces the risk of acquiring COVID-19 in healthcare settings. Yet, continuous monitoring of SARS-CoV-2 seroprevalence is needed to inform infection control strategies.
About the study
In the present study, researchers assessed SARS-CoV-2 seroprevalence and infection status among HCWs and administration staff of JUH over 13 months between 19 May 2020 and 22 June 2021. In addition, they identified potential risk factors for SARS-CoV-2-infected HCWs using a questionnaire enquiring about individual SARS-CoV-2 exposure. All 660 HCWs filled out this questionnaire at all three voluntary study visits. In addition, participants provided serum samples, and using these samples, the team assessed specific SARS-CoV-2 antibodies.
If testing showed that any participant(s) had antibodies against SARS-CoV-2 nucleocapsid (N) or spike (S) protein without receiving a vaccination or if their reverse transcription-polymerase chain reaction (RT-PCR) came positive, it implied they had SARS-CoV-2 infection. The questionnaire helped the researchers gather all needed information about the participants, including demographics, accidents with biological material, compliance concerning the use of PPE, serology and RT-PCR test results, and clinical symptoms. Further, it covered questions regarding household size, travel, working area, and individual exposure to confirmed COVID-19 cases. The team updated the questionnaire to include questions on the number and type of SARS-CoV-2 vaccinations.
Furthermore, the researchers compared SARS-CoV-2 infection rates among hospital staff working at different COVID-19 risk areas according to working place. HCWs, for instance, work in high-risk areas, while administration staff members do not come in close contact with patients.
During the study duration, serological (n=40) and RT-PCR (n=28) testing results evidenced that 44 HCWs had SARS-CoV-2 infection. Thus, only 406 of 660 participating HCWs were eligible for final analysis. Of these, 76, 198, and 132 were at high-, intermediate-, and low-risk, respectively, of contracting COVID-19 due to exposure from others. The risk of SARS-CoV-2 infection tripled among JUH staff members, from 3.2% at the first visit to 10.8% during the total study period.
Although workplace or occupational contact with COVID-19 patients was not a risk factor for infection, exposure to a COVID-19-positive household member and colleague posed a significantly higher risk, with an adjusted odds ratio of 4.46 and 2.30, respectively. Perhaps the high overall compliance of 92.4% among HCWs to wear PPE mitigated the risk because 67.4% of JUH staff members reported direct exposure to a SARS-CoV-2-positive patient.
The study analysis revealed that a nurse or non-clinical HCWs had an increased infection rate relative to a physician. This observation underlines the importance of educative measures, which might improve individual risk behavior in the non-occupational setting and warrants further investigation.
The study results showed that exposure to SARS-CoV-2-infected colleagues and household members imposed the highest risk in HCWs of JUH, rather than exposure to patients. Therefore, infection prevention strategies should focus more on personal contact between hospital staff members, strict adherence to mask use, and improved risk awareness outside the hospital.
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.