Andemicity of Covid-19 in Humans

Coronaviruses are named after the crown like spikes on their surface. SARS-CoV-2 is the novel coronavirus that causes coronavirus disease 2019 or COVID-19. When the invasion by SARSCoV-2 is limited or contained at sites of nasal passage and conducting airways around throat by both innate & acquired immune responses, COVID-19 can be mild, or even asymptomatic. But when the infective virions manage to move down and invade the gas exchange units of lungs called alveoli, it will be a serious life threatening damage. Not only that, infective virions can enter bloodstream (sepsis), leading to disseminated COVID-19. Sepsis occurs when infective virions of SARS-CoV-2 reach and spread through carrier bloodstream, causing tissue damage everywhere it goes as far as there are susceptible types of human body cells with welcoming hACE2 receptors on their surfaces. The infection or invasion of a human host for the first time by a pathogenic virus, (also known as a primary exposure to that specific virus) generates acquired immunity against that virus. So that if the same pathogenic virus enters the body of the same person it infected first, the immune response activated by the primary exposure will destroy it promptly. The only reliable approach to fight against viral diseases or infections is vaccination as there is nearly no medicine or chemotherapy to cure viral diseases except managing them. Vaccination of SARS-CoV-2 can be done or occurs in two possible ways, i.e., by natural infection and by health professionals. Thus, those people who have been infected by SARS-CoV- 2 and have been recovered from it will not have to take vaccination against COVID-19. The key objective of this paper is to impart the pandemicity and pathogenicity of COVID-19 including susceptible, types of human body cells, to SARS-CoV-2 infection. Nearly and inevitably, when all human populations are vaccinated naturally by infection and by health professionals against SARS-CoV-2 invasion, then it will be the end of pandemic COVID-19 in human populations of the globe. As the consequence of this it is the good of human life that overbalances the pain and evil of COVID-19; we are stepping to that optimistic end!!!!