Whole genome sequencing and analysis of the clinical implications of SARS-CoV-2 strains

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants that emerged shortly after the coronavirus disease 2019 (COVID-19) pandemic began have altered epidemiological and clinical findings; and these variants changed the course of this health crisis.

Whole-genome sequencing was performed on SARS-CoV-2 strains isolated from 21 patients with COVID-19. The frequency of structural changes in the virus and their effects on clinical findings of the disease were analyzed.

The spike Q493R mutation was detected more frequently in patients who had received four or more doses of a COVID-19 vaccine (p = 0.043). The clinical effect of the spike R346K and A263T mutations (reported in Türkiye for the first time) detected in a patient who had received four doses of the vaccine in the 3 months prior to being infected with COVID-19 could be related to escape from the antibody response. The spike R21T mutation may increase the virus's entry into intestinal cells; and, as a result it may be responsible for severe clinical course and gastrointestinal symptoms. The patient infected with the Omicron BA.2 subvariant with the spike L452M mutation exhibited a significant increase in inflammatory parameters; suggesting that this mutation may trigger an excessive immune response and hyperinflammation.

This is the first study based in Türkiye that evaluated the clinical impact of variations in the sequences of SARS-CoV-2 variants. There is a need for further investigation into the clinical impact of these results in a larger population spread over more centers, and more sequencing studies.