Mutations in SARS-CoV-2 nucleocapsid in variants of concern impair the sensitivity of SARS-CoV-2 detection by rapid antigen tests

Rapid antigen tests (RATs) are used as convenient SARS-CoV-2 to minimize infection risks in the private and public domain (e.g., access shops, concerts, sports, other social events). RATs are: however, less sensitive than quantitative reverse transcription Polymerase chain reaction (RT-qPCR) assays; hence, samples with low viral loads may be misdiagnosed. Reports on ability of detect variants concern (VOCs) Delta Omicron often only qualitative. We, therefore, examined analytical sensitivities four different for detection both full virus recombinant proteins relevant VOCs. Since most based nucleocapsid protein (N-protein), we constructed multiple N-protein mutants (mirroring specific amino acid exchanges VOC N-proteins) using prokaryotic expression plasmids site-directed PCR mutagenesis. Testing by revealed substitutions R203K R203M, critical sensitivity some RATs. Interestingly, R203M mutation completely abrogated even at high concentrations variant. As a proof-of-concept study, show that one or two changes can negatively impact Hence, antibodies such lateral flow assays should optimized target preferentially more conserved regions N-protein.