Table 1.

The Shell Disorder Models (SDMs). There are three closely related models based on the principles of protein intrinsic disorder. Levels of disorder are measured at each shell of the virus.

Year of First Publication	Shell Disorder Model	Details
2008	Parent Viral Shape-shifter Model	A database of viral shell proteins was built. HIV-1, HCV and HSV were found to have abnormally high disorder at their outer shells. No effective vaccine is currently available for the three viruses.
2012	CoV Transmission SDM	Correlations were found between disorder levels in M and N proteins and the modes of transmission; i.e., fecal–oral and respiratory transmissions.
2015	Virulence-inner Shell Disorder Model	Positive correlations have been found for virulence of many viruses and their inner shell disorder. Viruses include DENV, EBOV, NiV and SARS-CoV-1/2.