Designing and expression of recombinant fusion protein for screening SARS-CoV-2

Corona virus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), claimed many-a-lives globally. After the report of the first incidence of the virus, various variants have emerged with each posing a greater threat than its predecessors. Though many advanced diagnostic assays like real time PCR are available for screening of SARS-CoV-2, their applications are being hindered because of accessibility and cost. With the advent of rapid assays for antigenic screening of SARS-CoV-2 made diagnostics far easy as the assays are rapid, cost-effective and can be used at point-of-care settings. In the present study, a fusion construct was made utilising highly immunogenic epitopes from the three important structural proteins of SARS-CoV-2. The protein was expressed; purified and rapid antigen assay was developed. Eight hundred and forty nasopharyngeal swab samples were screened for the evaluation of the developed assay which showed a 37.14%, 96.51% and 100% positivity, sensitivity and specificity respectively. The assay developed was supposed to identify SARS-CoV-2 wild-type as well as variants of concern and variants of importance in real-time conditions.