A comparative study on the persistence and viability of SARS-CoV-2 wild-type and omicron variant on artificially contaminated surfaces: the role of fomites.

Indirect transmission of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been investigated but it is still not completely understood. The present study aimed to compare the persistence and viability of the lineage B.1 and omicron BA.1 subvariant in five daily-use materials to evaluate the role of fomites as a possible source of infection. Artificial contamination was performed in the first set of materials, ethylene vinyl acetate (EVA), cardboard, polystyrene, aluminium, and plastic. Further surfaces using BA.1 (glass, plexiglass, cotton, polyester, and tetrapak) were conducted. The persistence, viability of Vero E6 cell cultures and the residual infectivity of the two lineages were evaluated over 5 days. The results showed different stabilities between the tested matrices. In cotton and polyester, the RNA was undetectable in 24 and 48h post-contamination (p.c.), respectively, and the virus was not viable within 30 min, while in the other surfaces, both lineages, RNA was detectable until 120h p.c. A rapid decay of the viral load was revealed on cardboard, mostly for the omicron variant. Furthermore, on all the materials, longer stability of BA.1 was demonstrated, but showing a less intense CPE than the wild-type. EVA was the material that was able to better sustain virus stability as the virus developed CPE up to 72h p.c. In conclusion, the potential spread of SARS-CoV-2 through fomites is conceivable, albeit it is difficult to establish the real capacity to infect people. Nevertheless, thise information is fundamental to adopting the appropriate measures to mitigate the spread of SARS-CoV-2 and its variants.