Posted on April 16, 2020

As the world continues to self-isolate and fight both health and economic battles against the coronavirus (COVID-19), the race to find a drug that can be effective against the virus is proving to be a marathon rather than a sprint.

The death toll from COVID-19 has already surpassed 125,000, so there is understandable pressure to find an effective vaccine as fast as possible, but with so much at stake can the world’s scientists really afford to take shortcuts?

Before vaccines are fully approved, they usually go through three phases of clinical tests, which is why it has been suggested it could be at least a year until we have an accepted vaccine that has been proven to be effective against COVID-19. Prophylaxis (treatment given or action taken to prevent disease) is critical if we are to break the spread and rapid rate of increase of COVID-19. Specifically, chemoprophylaxis - the use of drugs to prevent disease - is required.

Pre-exposure and post-exposure prophylaxis are both required, and vaccines that are currently used to tackle malaria, HIV, influenza and lung inflammation are among the hundreds being tested. Anti-malarial agents chloroquine and hydroxychloroquine are among those being considered for the treatment of the virus, having already been used in the treatment of viral infections such as Severe Acute Respiratory Syndrome (SARS) and hepatitis among others. COVID-19 resulted from the SARS-CoV-2 virus, which is a mutated form of the original SARS coronavirus of 2003, and as these drugs were effective in treating the previous SARS virus, they are now being tried on the new mutated one. 

Chloroquine has been used to treat and prevent malaria since 1934 and is on the World Health Organization (WHO)’s Model List of Essential Medicines, which contains the medications considered to be most effective and safe to meet the most important needs in a health system. It is synthesized from quinine which has been isolated from the bark of a tree known as cinchona. Hydroxychloroquine is a derivative of chloroquine and was developed to combat strains of malaria that are resistant to chloroquine, and it therefore has greater potency. Sold under the brand name Plaquenil among others, it was approved for medical use in the United States in 1955 and is also on the WHO Essential Medicines list.

Taken in tablet form, chloroquine and hydroxychloroquine have been extremely effective against malaria. They enter the red blood cells, which is where the malaria parasite usually lives and multiplies during infection, and they kill the parasite as well as preventing its multiplication. The drugs have an antiviral effect as they inhibit nucleic acid synthesis and they have been used in the treatment of certain viral infections like SARS and hepatitis among others, which is why some physicians and centers have tried it in the treatment of the COVID-19 pandemic. Clinical trials in China, where COVID-19 was first detected at the end of 2019, have suggested that chloroquine shortens the course of the virus, improves lung function, inhibits exacerbation of pneumonia, and promotes virus clearance.

Although testing is ongoing, clinical trials for both drugs have shown good results in viral clearance from patients affected, especially when used in conjunction with Azithromycin (Zithromax). The Food and Drug Administration (FDA) has already issued an Emergency Use Authorization that will allow patients suffering from COVID-19 to be treated using chloroquine phosphate and hydroxychloroquine sulfate. They are also being used by Hamad Medical Corporation as a therapeutic protocol in conjunction with Zithromax.

These drugs have been used for a very long time in the treatment and prevention of malaria, and have a safety record. There are some side effects just like with any other medications, the main one being on the retina of the eye and also on the heart which can result in arrhythmia - a problem with the rate or rhythm of the heartbeat - in certain cases. However, these drugs should only be taken if prescribed. People must not self-medicate as that can be extremely dangerous. My advice is not to take the medication without a physician’s approval, but I do recommend it to be used by medical staff who are in contact with COVID-19 patients to reduce the risk of them also becoming infected.

Companies all over the world are working day and night to produce a very large quantity of these drugs, which are now available in millions, and the good news is they are among the cheapest medications available in pharmacies, with a bottle of 30 tablets costing just $2-3. As I mentioned in my recently published paper ‘A recommendation for the use of Chloroquine, Hydroxychloroquine, Primaquine, or Tafenoquine for Prophylaxis Against the 2019 Novel Coronavirus’, these drugs can prevent the spread of this disease as they proved to be very effective in the prevention of malaria.

Dr. Fouad Alshaban is a Senior Scientist at Qatar Biomedical Research Institute, part of Hamad Bin Khalifa University, where he leads the Autism Epidemiology Research Team within the Neurological Disorders Research Center.