Abstract
Clinical, experimental, and computational evidence of COVID-19 virulence and infectivity has been linked to SARS-CoV-2 shell disorder. A strong link was first discovered using an AI disorder-predicting tool, which detected an unusually hard (low disorder) outer shell among all SARS-CoV-2-related viruses but not in the 2003 SARS-CoV-1. This could account for the high infectivity found in SARS-CoV-2-but not in SARS-CoV-1-as it is believed that hard shells protect viral particles from the onslaught of the antimicrobial enzymes present in the respiratory system and saliva. As a result, much larger quantities of particles are shed by COVID-19 patients. Abnormally hard outer shells (M) are associated with burrowing animals, e.g., pangolins, and SARS-CoV-2 likely acquired these shells due to its long-term evolutionary interactions with pangolins. As for virulence, the inner shell of SARS-CoV-2 (N) has been found to exhibit lower disorder than that of SARS-CoV-1. This lower disorder is consistent with the fact that SARS-CoV-2 is less virulent than SARS-CoV-1, as higher disorder in the inner shell is associated with more efficient protein-protein binding during replication. The link between N/M disorder and virulence or infectivity falls under the umbrella of shell disorder models (SDMs), which can connect virulence, infectivity, and long COVID under one coherent concept. Evidence of the reliability and reproducibility of SDMs as applied to COVID-19 is examined. The hard M that is resisting the antimicrobial enzymes in the respiratory system can be extended to immunological enzymes, especially those found in phagocytes such as macrophages, which can therefore become a reservoir for the virus.