In December 2020, CTK shared that we had no reason to believe that the U.K. variant would affect the OnSite COVID-19 Ag Rapid Test’s performance, and we would work on confirmation studies. Since then, multiple SARS-CoV-2 variants have been circulating globally, which led us to include them in our confirmation studies.
The OnSite COVID-19 Ag Rapid Test detects the presence of antigens from the SARS-CoV-2 virus, namely the viral Nucleocapsid Protein (NP). By analyzing the NP mutations present in the U.K. variant, South Africa variant, and Brazil variant, mapping the SARS-CoV-2 NP domain recognized by the OnSite COVID-19 Ag Rapid Test using ELISA and peptide scanning, and testing recombinant full-length NP and NTD (monomer) at different concentrations, we have shown that the OnSite COVID-19 Ag Rapid Test is not impacted by the mutations from the U.K., South Africa, and Brazil variants.
The OnSite COVID-19 Ag Rapid Test can detect the NP mutants with mutations from the U.K., South Africa, and Brazil variants. All mutations present in the NP protein of these three variants do not map to the epitopes of the antibodies used in our Rapid Test. In the future, by surveilling and analyzing if new variants have mutations within two antibodies’ epitopes, we can predict any possible impact on the performance of CTK’s OnSite COVID-19 Ag Rapid Test.
To read the white paper, click here
Zhang, L, Zhang, B, Lorenzo, L, Ridin, A, Liberal, V. (2020). OnSite Covid-19 Ag Rapid Tests detect newly identified U.K., South Africa, and Brazil SARS-CoV-2 variants [White paper]. CTK Biotech.