Usefulness of rapid antigen testing for SARS-CoV-2 screening of healthcare workers: a pilot study.

BACKGROUND: Identification of infected healthcare workers (HCWs) is an important step in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) transmission control. Rapid antigen tests (RATs) are considered an important addition to molecular tests in diagnosing coronavirus disease 2019 (COVID-19), mainly because of their fast turnaround time, easier analytical procedure and lower price. However, real-life studies on the usefulness of such testing for screening of HCWs are limited. METHODS: Physicians, nurses and hospital attendants currently working at the University Clinic of Respiratory and Allergic Diseases Golnik were invited to participate in the pilot study. Nasopharyngeal swabs were obtained three times per week for two consecutive weeks and tested with a point-of-care RAT and reverse transcription polymerase chain reaction (RT-PCR). Serum samples were obtained at the beginning of the study and 2 weeks after the last swab was collected to evaluate the serological status. RESULTS: A total of 191 nasopharyngeal swabs from 36 HCWs were obtained. None of the samples tested was positive for the presence of SARS-CoV-2 antigen, whereas two HCWs tested positive on RT-PCR. Of these, one HCW had a newly identified SARS-CoV-2 infection, whereas RT-PCR probably detected a previous but recent infection in the other HCW. CONCLUSION: Based on the results of this pilot study, it is unlikely that RAT will reliably detect novel SARS-CoV-2 infections among asymptomatic HCWs despite serial sampling. Although RT-PCR-based screening of HCWs may not be feasible due to high sample volume, molecular methods may identify SARS-CoV-2-infected HCWs already during the presymptomatic stage. Trial registration number NCT04716088, 19.1.2021, retrospectively registered.