In 2005, a study sponsored by CDC in U.S. showed that Chloroquine could neutralize SARS virus in cells that were infected with that virus in the laboratory ( that is called an in-vitro study).
In January of 2020, a group of Chinese investigators looking to replicate those results in SARS-Cov-2 published an article looking at Chloroquine to see if it could kill this new virus in vitro. The results were positive .
Chloroquine has two widely different properties. It is an antimicrobial agent shown to have potency against viruses and parasites. But it also has immunomodulatory effect. That means that it can affect the immune system. Recall that in my previous post I explained that COVID-19’s virulence is compounded by its uncanny ability to cause the human body to create a self destructive cytokine storm. Chloroquine has been used extensively in patients with autoimmune diseases such as lupus and rheumatoid arthritis to reduce the cytokine surge.
Let’s focus on the historical use of the antimicrobial properties of chloroquine first. Chloroquine has been shown to be effective in the laboratory in fighting many viruses including the zika virus, ebola, and avian influenza virus H5N1. But in live animals or humans the results have not been promising.
The Chinese started using chloroquine quite early on and in February, The Chinese Health officials recommended the use of chloroquine in all COVID-19 hospitalized patients based on their experience of 100 patients with reported improved outcomes. There is no actual publication with data to back this up so apparently we just have to take their word for it.
In March, a group of French researchers from the University of Marseille reported on 20 patients who got hydroxychloroquine ( a similar but safer version of chloroquine). Those patients improved faster than patients in another hospital who didn’t get the drug (not exactly the most sophisticated study). Furthermore, in May, these same French scientists enthusiastically reported on their discovery of an important way that the drug could bind the virus and neutralize it in laboratory.
Many small ‘positive’ studies followed, And then, The Institute of Medical Research in Chandigardh, India reported that after looking at 16 international studies they could only conclude that patients on hydroxychloroquine had less progression of pneumonia on xray but otherwise nothing encouraging.
Finally a randomized double blind placebo controlled trial at Veterans Administration showed that there was no benefit in giving this drug to severely ill COVID-19 patients. In fact, there was some harm.
I want to bring out a couple of conclusions:
1. At this point the studies on hydroxychloroquine have all been small, poorly designed and not impressive.
2. We do not know if hydroxychloroquine is beneficial in patients as a prophylaxis to ‘prevent’ COVID-19 , the way it is used for malaria prophylaxis. We need a well designed study. It may very well be. But don’t know.
3. We need multi-national well designed trials with large number of patients for statistically more reliable results at different phases (pre-infection, early, middle and late presentation) of this disease.
As always, please refrain from political commentary. But more to come on vitamin D and Zinc and COVID-19. Keep liking and sharing please.