Background: The mutation of a new virus is key to its ability to adapt, as it allows the virus to change and survive in new environments. We try to capture the full extent of SARS-CoV-2 diversity in Asturias. Methods: Samples from nasopharyngeal swabs belonging to SARS-CoV-2 infected patients were characterized by the whole genome sequencing. Results: A total of 4,001 sequences were analysed between 2020 and July 2024. During this time, 5302 mutations were found (157 occurred in more than 5% of the viral population). Between 2022 and 2024, 88 new non-synonymous mutations occurred in over 5% of the viral population, of which 31 are currently maintained and were fixed 250±46 (93-620) days after their appearance. Besides, 55 new circulating variants (NCVs) belonging to 41 pangolin lineages were detected. Of these NCVs, 24 were originated throughout the world, and the other 31 in Asturias (10 were only detected in the region, 8 also in Spain, and 13 around the world).Conclusions: New variants circulating around the world continually appear in our region, leading to a constant rotation of lineages. Although most of the changes have little or no impact on the virus's properties, the continued emergence of new variants warrant continued genomic surveillance.

The Potassium Ribosate, which has been shown to have an enhancer effect in limiting replication and viability in cancer cells, also appears to show promise in alterating viral replication. To determine its activity against SARS-CoV-2, an inhibition assay was performed using 26 strains obtained from clinical samples from patients isolated on the Vero E6 cell line. For this, the strains were serially diluted and treated with 125mM Potassium Ribosate. The Potassium Ribosate was administered at a single concentration (125mM stock) in two ways: 24 hours before infection and in the culture medium after removal of the infectious inoculum. The culture medium was changed 3 days after inoculation. Seven days after inoculation, a visual reading of the cytopathic effect (ECP) and RT-qRCP were performed to calculate the viral load. Reduction of 3log (9Ct) between with or without Ribosate was considerate a very good response. Of the 26 evaluable strains, a reduction in viral replication was observed in 13 (50%) and 16 (61.5%) of the pre-treatment and treatment study (p=0.29). This response was good or very good in 10 (38.4%) and 11 (42.3%) (p=0.4), respectively. Potassium Ribosate administration reduced the viral load of SARS-CoV-2 cultures in Vero E6 cells in more than half of the cases, both at infection and pre-infection administration.