Coronavirus disease 2019 (COVID-19) has spread to almost every part of
the globe. Numerous risk factors have been identified for predisposition to severe
infection. Age is reportedly an incredibly significant risk factor due to high fatality in
the elderly population. Further, the infection is more predominant in males as
compared to females, probably due to the difference in immunity, hormones, and some
specific habits (smoking, drinking) that may influence the viral infection. Correlation
of blood group with SARS-CoV-2 infection is also reported as individuals with type A
blood group are probably more susceptible to the infection since it is native form. Type
O blood group is an evolved form, and thus individuals with this group may be less
susceptible to the infection. In addition, existing comorbid conditions like
hypertension, diabetes, cardiovascular, endocrine, and chronic respiratory diseases are
also associated with an increased risk of severe COVID-19. Obesity has also been
reported to have a huge impact on the infection rate and post-infection results. There is
also an apprehension of vertical transmission from pregnant females to foetus, but this
aspect needs to be analysed in detail in future studies. This review summarizes the
effects of different risk factors like age, gender, comorbidities, blood group and
prenatal transmission on SARS-CoV-2 infection. The correlation of viral infection with
genetic predisposition is another factor that can be explored in future studies. Detailed
clinical studies involving large patient groups are required across the globe and on
different ethnic populations to clearly define the role of risk factors to COVID-19.
Keywords: Age, Blood group, COVID-19, Diabetes and obesity, Gender,
Hypertension, Risk factors.
