Asymptomatic Carriers/Patients with COVID-19 Infection: How is this Possible?

A sizeable proportion of individuals contracting the corona virus disease 2019 (COVID-19) infection remains asymptomatic, while some patients develop mild symptoms and others exhibit severe symptomatology becoming critically ill necessitating admission to intensive care unit exposed to a high mortality risk. The pathophysiological mechanisms underlying this diversity in the clinical picture of COVID-19 are poorly understood. A variety of reasons have been postulated, among which, viral load, age, gender, immune response, blood type, genotypes, polymorphisms, comorbidities and pre-existing immunity are actively explored. Thus, there is a dire need to further elucidate this phenomenon and find ways to identify and discern susceptible from resistant individuals with the ultimate goal to find a cure for the disease. These issues are herein discussed and pertinent recent literature is reviewed. [ABSTRACT FROM AUTHOR]