Understanding Viral Infection Mechanisms and Patient Symptoms for the Development of COVID-19 Therapeutics.

International journal of molecular sciences. 2021;22(4)

Plain language summary

The outbreak of a novel coronavirus was reported in Wuhan, in the Hubei province of China, in December 2019. This virus was officially designated as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) because of its phylogenetic and taxonomic similarities to other coronaviruses. The aim of this review was to understand the viral infection mechanisms of SARS-CoV-2, the clinical features of Covid-19 and the mechanisms through which Covid-19 can be effectively treated with existing drugs. Literature shows that: • SARS-CoV-2 is usually transmitted by inhalation or contact with infected droplets. Inhaled droplets or aerosol carrying the virus then infect and spread through the respiratory tracts. • Severe inflammatory response is a remarkable feature of Covid-19 symptoms. This is caused by delayed viral clearance, which induces chronic systemic inflammation and widespread tissue damage, even leading to cytokine storms. • The incubation period is generally 5-6 days, but it ranges from one day to as much as two weeks. • Interstitial pneumonia and subsequent acute respiratory distress syndrome are the leading causes of death in patients with Covid-19. • There is no licensed treatment for Covid-19, only a combination of antiviral and anti-inflammatory drug treatments are being used. Authors conclude that their finding may provide new insights into the development of therapeutics by understanding the various clinical and basic research studies currently underway.


Coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 virus, has become a worldwide pandemic. Symptoms range from mild fever to cough, fatigue, severe pneumonia, acute respiratory distress syndrome (ARDS), and organ failure, with a mortality rate of 2.2%. However, there are no licensed drugs or definitive treatment strategies for patients with severe COVID-19. Only antiviral or anti-inflammatory drugs are used as symptomatic treatments based on clinician experience. Basic medical researchers are also trying to develop COVID-19 therapeutics. However, there is limited systematic information about the pathogenesis of COVID-19 symptoms that cause tissue damage or death and the mechanisms by which the virus infects and replicates in cells. Here, we introduce recent knowledge of time course changes in viral titers, delayed virus clearance, and persistent systemic inflammation in patients with severe COVID-19. Based on the concept of drug reposition, we review which antiviral or anti-inflammatory drugs can effectively treat COVID-19 patients based on progressive symptoms and the mechanisms inhibiting virus infection and replication.

Lifestyle medicine

Patient Centred Factors : Mediators/Covid-19
Environmental Inputs : Microorganisms
Personal Lifestyle Factors : Environment
Functional Laboratory Testing : Not applicable

Methodological quality

Jadad score : Not applicable
Allocation concealment : Not applicable
Publication Type : Journal Article ; Review


Nutrition Evidence keywords : Gastrointestinal ; Ferritin