The host’s wide range of genetic variation plays an essential role in
determining the susceptibility, severity, and overall pathological conditions of
coronavirus disease-19 (COVID-19) following infection with severe acute respiratory
syndrome-coronavirus-2 (SARS-CoV-2). COVID-19, caused by SARS-CoV, is a
zoonotic disease that has affected humans after crossing boundaries. Emerging viral
infections typically result from the host when a virus transfers from the very first host
into a new species. There is substantial diversity in illness progress among patients
infected with SARS-CoV-2. Many do not show any manifestations, while others
progress to acquire COVID-19; nonetheless, the intensity of COVID-19 symptoms
substantially ranges among people. Host factors such as age, gender, geographical
region, diseases, co-morbidities, and various host genetic factors predispose
susceptibility to SARS-CoV-2 infection. Individuals who possess certain variations of
genes directly implicated in viral infection (e.g., ACE2, TMPRSS2) or who have
differential expression of those genes may be more susceptible to SARS-CoV-2. These alterations might account for the wide variety of symptoms and severity of COVID-1-
-related SICKNESS in various people. Because the behavior of the infectious agent
varies so much across strains, the impacts of individual variation are best evident when
the same strain of an organism infects previously unexposed people simultaneously. An
increase in genetic diversity in host sensitivity to pathogenic agents has been related to
the development of major-effect resistance polymorphisms among populations.
Keywords: Host genetic factors, Human leukoc
