Assessment and Comparison of Two Serological Approaches for the Surveillance of Health Workers Exposed to SARS-CoV-2

Antonio Russo,1 Federica Calò,1 Alessandra Di Fraia,1 Mario Starace,1 Carmine Minichini,1 Valeria Gentile,1 Italo Francesco Angelillo,2 Nicola Coppola1 On behalf of the Vanvitelli-COVID-19 Group1Department of Mental Health and Public Medicine, Section of Infectious Diseases, University of Campania, Naples, Italy; 2Department of Experimental Medicine, University of Campania, Naples, ItalyCorrespondence: Nicola Coppola Department of Mental Health and Public Medicine, Section of Infectious DiseasesUniversity of Campania, via: L. Armanni 5, Naples 80131, ItalyTel +39 0815666719Fax +39 0815666013Email nicola.coppola@unicampania.itBackground and Aim: The aim of the present study was to assess the diagnostic performance of an LFA compared with an ELISA test in a cohort of HWs operating in a COVID-19 unit of a teaching hospital in southern Italy.Methods: We performed an observational, prospective, interventional study including 65 COVID-19 unit personnel. On a total of 196 serum samples (at least 2 serum samples for each HW), LFA and ELISA tests for SARS-COV-2 IgG and IgM were performed. Also, 32 serum samples of SARS-CoV-2 RNA positive patients at least 21 days before sampling, and 30 serum samples of patients obtained up to November 2019, before COVID-19 outbreak in China, were used as positive and negative controls, respectively.Findings: Of the 65 HWs enrolled, 6 were positive in LFA; overall, of the 196 serum samples, 20 were positive in LFA. All ELISA tests performed on serum samples collected from HWs were negative. The specificity of LFAs was 90.77% considering the 65 HWs and 89.80% considering all the 196 health workers serum samples analyzed. Considering the data on HWs, ELISA test for SARS-COV-2 antibodies showed a specificity of 100%, including all the 196 serum samples collected, and 100% including the 65 HWs. The ELISA and LFAs performed after 21 days last COVID-19 patient was discharged were all negative.Conclusion: LFAs compared to ELISA tests result in less specificity, considering COVID-19 negative personnel and patients. Thus, LFAs seem to be not adequate in the active surveillance of HWs.Keywords: health workers, COVID-19, SARS-CoV-2, anti-IgG SAR-COV-2, active surveillance