Investigation the reasons for varying the severity of COVID-19 from person to person: A review study

COVID-19 is caused by the SARS-COV-2 virus and mainly affects the lung tissue. In addition, other tissues are attacked by the virus. Reports have shown that clinical manifestations in Covid-19 patients vary from asymptomatic to acute respiratory symptoms in the lung and septic shock affecting the immune system in other organs. This review article aimed to investigate the molecular mechanisms associated with SARS-COV-2 pathogenicity and the relationship between these mechanisms and the severity of various clinical manifestations in patients.

Published articles by researchers in PubMed and Google scholar databases from 2019 to 2021 were collected and reviewed based on the keywords SARS-COV-2, COVID-19 and disease severity.

After entering the SARS-COV-2 virus into the body and the activation of the immune system for reasons such as increased NET production, oxidative stress, activation of cell death pathways including ferroptosis and finally the explosion of cytokine storm and pyroptosis, exacerbate the severity of the disease and increase mortality. In addition, the molecular expression of NLRP3 can play a major role in the development of cytokine storms in patients, some depend on their immune system to fight the virus due to the proliferation of NLRP3 and other destructive molecular mechanisms, thus showing the different severity of the disease.

Individuals in the community show varying degrees of Covid-19 disease depending on the different reactions of their immune systems. Various cellular and molecular mechanisms appear to be activated in sufferers that NLRP3 expression plays a large role.