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.