Variantes de SARS-CoV-2, una historia todavía inacabada

Mutations in the SARS-CoV-2 genome can affect the gene encoding the Spike (S) antigen, which interacts with the host cell specific receptor, selecting mutant variants with changes in their infective capacity, pathogenic potential and resistance to neutralizing antibodies. The nomenclature to design the variants uses a colloquial form referred to the country or place of detection, a code from the “Pangolin” database and one from the “Nextstrain” page. New variants that have spread include the British B.1.1.7 (20I/501Y.V1), the South African B.1.351 (20H/501.V2), the Brazilian P.1 (20J/501Y.V3), the Californians B.1.427 B.1.429 (20C/S:452R) and the most recent, the Indian B.1.617 (VUI-21APR-01). The gold standard for the identification of the variants is whole genome sequencing. However, real-time PCR techniques have already been developed for the detection of specific mutations that can facilitate their presumptive identification. The impact of these variants on global vaccination programs has raised concern. It is generally thought that, since the response evoked by the vaccine against the S antigen is directed at the entire protein and the mutations only affect specific regions, the escape effect of the vaccine antibodies will be limited. Among the future strategies proposed for immuno-protection, the increase in the number of doses, the alternation of vaccines and the development of specific vaccines against different variants has been suggested.