Three SARS-CoV-2 variants of potential concern have recently been identified, characterized by several novel genetic mutations.1,2 Although mutations in viral genetic sequences have the potential to alter the performance of diagnostic tests, based on analysis of the specific mutations carried by the two novel variants, it is expected that the majority of tests currently used in primary detection of SARS-CoV-2 will be unaffected.

However, laboratories should be aware of potential effects on certain diagnostic tests. The image below the table shows the SARS-CoV-2 genome, mutations reported across the three variants, and the specific genetic region targeted by several molecular and antigen-detection assays. Notably, the B.1.1.7 and B.1.351 variants have been associated with higher viral loads compared with existing variants in preliminary analyses,6,7 resulting in lower cycle threshold (Ct) values for PCR testing. Detection rates with antigen tests may increase due to increased concentration of antigen in samples.

Both the B.1.1.7 and B.1.351 variants have been associated with higher transmission rates compared with existing variants, suggesting that they carry a selective advantage.2,8 There is no evidence yet of a change in transmissibility with the P.1. variant, however, the presence of shared mutations with the B.1.1.7 and B.1.351 variants indicates that increased transmissibility is plausible.9 The impact of the novel mutations carried by the three variants on pathogenicity or resistance to antibodies or vaccines is yet to be determined.

The rapid emergence of these three novel variants clearly demonstrates the need for continued, robust and widespread SARS-CoV-2 surveillance, to ensure that other novel mutations are identified as early as possible.

Regards

Alex

Submit your manuscript: https://www.longdom.org/submissions/infectious-diseases-preventive-medicine.html