Three fast-spreading new variants of SARS-CoV-2 virus have emerged in recent months: the U.K. variant B.1.1.7, the Brazil variant P.1, and the South Africa variant B.1.351.

A subset of the mutations identified in the RBD domain of the spike protein occurs in more than one strain, although the three variants are believed to be independently evolved. These convergent mutations, specifically, the N501Y (shared by all three, 40592-V08H82) and E484K (shared between B.1.351 and P.1, 40592-V08H84), are of high interest because they may be the cause of the increased transmissibility.

The mutations in these strains also occur in the nucleocapsid protein, which is commonly used as the biomarker in rapid antigen tests. It’s critical to assess whether the current commercial antigen tests can detect the mutated N proteins with the same sensitivity and specificity as their WT counterpart.

Sino Biological has developed 80+ recombinant RBD/Spike and N protein mutants carrying the mutations of high interest, such as N501Y and E484K identified in three fast-spreading SARS-CoV-2 variants, U.K. B.1.1.7, Brazil P.1, and South Africa B.1.351, emerging in recent months.