CoViD-19 Susceptibility.

There have been over five million cases of infection with the second Corona virus to induce SARS (SARS-CoV2) and close to half a million deaths worldwide since the first report of Corona Virus Disease in late December 2019 (CoViD-19). Over two million CoViD-19 patients have recovered. The factors and variables that lead certain CoViD-19 patients to survive this otherwise aggressive and lethal viral infection are intensely researched, as is the development of productive anti-virals and of safe and effective vaccines. Several hypotheses invoke putative mutations of the ss-positive RNA SARS-CoV2 virus to states of stronger or weaker virulence and lethality. Other hypotheses propose that the patient's status of immunity, vitamin D level, Zinc deficiency or other physiological parameters determine how any given patient will effectively weather the viremia and the consequential multi-symptomatic CoViD-19. The initial cause - causa prima - underlying all the symptoms of CoViD-19 is infection of the host human cell by SARS-CoV2. The virus spike (S) protein finds its binding site, ACE2, widely distributed in all cells and tissues that potentially proffer CoViD-19 pathology. S consists of two subunits, S1 and S2, which are cleaved by the widely expressed transmembrane protease serine 2 (TMPRSS2) before the virus fuses to the plasma membrane and infects the cell. Current trends show that variant alleles resulting from single nucleotide polymorphisms (SNPs) of ACE2, and genetic variants of TMPRSS2, with putative distinct affinities for S clip, may determine a complex multi-factorial spectrum of SARS-CoV2 virulence across patients, and predict CoViD-19 susceptibility.