SARS-CoV-2 rapidly evolves lineage-specific phenotypic differences when passaged repeatedly in immune-naïve mice

The persistence of the SARS-CoV-2 virus, despite vaccines and some level of immunity in the population, is because the virus is changing over time, making vaccines and treatments less effective. In this study, researchers looked at how the virus changed after being passed through mice expressing the human ACE2 receptors. They found that the later versions of the virus caused more severe illness in both the whole body and the lungs, and the Delta variant showed resistance to antibodies neutralization and interferon production, which is a substance that helps the immune system. The resistant traits were linked to a specific mutation in the virus called S371F, which is also found in the Omicron variant. This mutation, along with another one called E1182G, is associated with interactions in the human body that affect how the virus enters cells and how the immune system responds. Overall, the study shows that SARS-CoV-2 tends to change over time with real-world consequences, and the changes can vary depending on the specific lineage or variant of the virus.

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