Coronavirus: How Chloroquine and Other Antivirals Inhibit the Virus


Every day, scientists go into their laboratories and discover something new about the most recent coronavirus (COVID-19) outbreak. This explains why two months after the first ever case was reported, there are now three drugs expected to halt the proliferation of the virus in the body.

In all, more than 80 clinical trials have been launched to test coronavirus treatments including a stem-cell trial where scientists infuse patients with stem cell from menstrual blood.

It has been a battle to save lives and also, for both new and existing drugs to prove their worth.

As at February 21, nine vaccines and four drugs undergoing clinical trial have shown signs that they can handle the virus inside the human body. Of all the drugs, only three: Favilavir, Remdesivir and Chloroquine have been approved for use in patients infected with the virus.

Already, Favilavir and Remdesivir have been successfully used to treat coronavirus patients.

Coronavirus: How Chloroquine and Other Antivirals Inhibit the Virus

So how did the anti-malaria, Chloroquine come into the picture?

On February 4, Cell Research Journal published a study by researchers, majority from the Wuhan Institute of Virology, which declared remdesivir and chloroquine to be effective drugs in the treatment of the coronavirus.

Also, early data from trials being performed in China as noted by the Deputy Head, China National Centre for Biotechnology Development, Sun Yanrong revealed that chloroquine phosphate could help treat the new coronavirus disease, Covid-19.

Again, what does a defunct anti-malarial agent have to do with a virus as potent as the coronavirus?

The answer is, a lot.

Chloroquine has a broad spectrum anti-viral effect. Before now, there have been numerous HIV-drug trials involving chloroquine and its derivative, hydroxychloroquine. It has been discovered that they are able to inhibit glycosylation of viral receptors and induce production of non-infectious retrovirus particles in HIV-1.

According to the research, this forgotten anti-malarial agent is found to inhibit the virus as it enters and exits the body cells. It slows the progression of the infection and interferes with the glycosylation of the viral receptors in the host cell. It is able to achieve this in low micromolar concentrations.

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This discovery about chloroquine is not unexpected. A research following the 2002 SARS coronavirus outbreak, a similar viral outbreak also in China, already demonstrated chloroquine’s potency against infections related to the coronavirus family.

The main problem regarding chloroquine is at what stage of the infection it can be effectively administered to someone sick with the coronavirus.

The second drug according to the Cell Research study is remdesivir. It is a nucleoside analog which shuts down transcription and synthesis of viral RNA.

Remdesivir was originally intended to treat the Ebola virus but failed during the human trials and replaced by more effective drugs.

However, with the new coronavirus, remdesivir and its manufacturers can make a timely comeback. In the United States, an infected patient was successfully treated with the drug and this has made the drug popular among researchers.

If remdesivir will eventually get approved, it is not going to be without some controversy. The research team at Wuhan Institute of Virology that facilitated the Cell Research study has filed a patent for the drug owned by the Gilead company in the United States. We don’t expect the manufacturers at Gilead to give up their intellectual property rights that easily.

Favilavir is the first ever coronavirus drug approved for use in patients. Before it was approved, a cruise ship of 2,666 passengers had been ravaged by the coronavirus and globally, 1863 deaths have been recorded.

Favilavir, an anti-viral product of a Chinese-based pharmaceutical company was originally developed to treat nose and throat inflammation caused by viruses.

The drug was cleared for use after it proved effective in a clinical trial of 70 patients with the virus. However, not much is known about the action of this antiviral drug because specific results of the clinical trial is yet to be released.

It is important to note that only Favilavir has been approved as a medicine for the new coronavirus. Remdesivir and chloroquine have only been cleared for human trials. They will be officially approved for use if they prove effective in reducing mortality rate among the human subjects infected with the virus.

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Scientists have preferred to stick with pre-existing drugs in their search for the coronavirus treatment. It is a common thing during epidemics to use available drugs to control it as quickly as possible. This is because developing a new drug is painstakingly time consuming. It takes at least 10 years for a new drug to complete the journey from initial discovery to the market place.

The infection would have gone out of control and many lives lost before a drug is ready.

The coronavirus epidemic will not be the last of its kind and scientists know that.

For the future, scientists are building on available research works gathered from the two previous coronavirus outbreaks (SARS and MERS) as well as this current outbreak. They want to produce a one-in-all drug that would be able to combat the multiple strains of the coronavirus including the ones that haven’t surfaced yet.

We hope that we do not see a repeat of what happened during the SARS coronavirus outbreak, where the work starts and then stops as soon as the epidemic is gone.



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