Chloroquine as a Promising Anti-Viral Drug in Immunocompromised Patients Amidst the COVID-19 Pandemic

Simran Kaur ‘20

Fig 1. COVID-19 infects individuals by attacking both the upper and lower respiratory tracts, causing serious symptoms including pneumonia, ARDS, respiratory failure, and possibly death. 

SARS-CoV-2, a new type of coronavirus, is responsible for a global pandemic that currently has infected hundreds of thousands of individuals worldwide. The virus belongs to the same family of viruses responsible for certain cases of the common cold, Middle East Respiratory Syndrome, and Sudden Acute Respiratory Syndrome (SARS). The virus is incredibly contagious, spreading through respiratory droplets and exploiting commonly-found human enzyme furin in order to proliferate quickly. Chloroquine is an anti-malarial drug that in studies has also shown efficacy in treating and preventing SARS, another coronavirus-caused condition. Researchers in this experiment sought to determine the efficacy of chloroquine as treatment in patients diagnosed with COVID-19 by analyzing a group of 100 Chinese patients. 

In a study conducted by China National Center for Biotechnology, all 100 diagnosed patients were treated with 500 mg chloroquine phosphate tablets that were administered orally twice a day for a total of 10 days. Pharyngeal swabs were performed daily to test for viral nucleic acids, bloodwork and myocardial enzymes were checked every alternate day, and chest CTs were performed before discharge. Discharge criteria consisted of return of body temperature to normalcy for at least 3 days, improvement in respiratory symptoms, and CT imaging presenting significant decreases in pulmonary inflammation. Some observed adverse reactions include dizziness, nausea and diarrhea, headache, and other minor symptoms. However, chloroquine in large and unmonitored doses has been known to cause retinal damage and cardiomyopathy. 

Chloroquine has been studied to interfere with the proliferation of coronaviruses in numerous different ways. The drug can inhibit an early step in the viral cycle by interfering in the biosynthesis of sialic acids, involved in ligand recognition and the binding of the virus to cell surface receptors. It can also disrupt the post-translational modification of virally-manufactured proteins through pH modulation, which impairs the maturation of viral proteins. A common complication of COVID-19, especially in older patients, is a cytokine storm, the sudden surge of immune cell production in the lungs, which exacerbates respiratory symptoms and inhibits breathing. Chloroquine can prevent the occurrence by regulating pro-inflammatory cytokines through inhibition of MAPK, which is required to be activated in order for viruses to complete replication. This study demonstrates the promising ability of chloroquine in alleviating and reducing pulmonary symptoms in patients diagnosed with COVID-19. With no approved treatments, and a vaccine estimated to not be ready for at least another 12 months, chloroquine can help the hundreds of thousands of patients struggling with the illness worldwide, and the millions more estimated by the WHO to be infected. 


  1. C.A. Devaux, et al. New insights on the antiviral effects of chloroquine against coronavirus: what to expect for COVID-19? International Journal of Antimicrobial Agents, (2020).
  2. Image retrieved from:×852.png

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