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Health A to Z  —  9 minutes

Fighting COVID-19 while we wait for a vaccine

June 4th, 2020
Raymond Lepage, PhD, Doctor in Biochemistry
Raymond Lepage, PhD, Doctor in Biochemistry
Science popularizer

According to the World Health Organization, as of April 1 there were nearly 700 clinical studies underway around the world to treat COVID-19 [1]. In Canada, about 20 studies have already been authorized [2], including about 10 in Quebec [3]. This wealth of research underscores the urgency of the fight against COVID-19, which has killed hundreds of thousands of people around the world. From a practical standpoint, this abundance also reflects the many economic incentives available for research. The group that patents the first successful, widely marketed drug will have its financial future guaranteed for decades to come, not to mention prestige for the people behind the discovery. Between hydroxychloroquine, colchicine, remdesivir, convalescent plasma and other treatments, who will win the race? Let’s try to get a clearer picture.

To understand how to fight SARS-CoV-2, we must consider all the steps involved in controlling the virus:

  1. Limit the virus’ presence in the environment.
  2. Prevent the virus from reaching the respiratory tract.
  3. Destroy the virus once it enters the body.
  4. Prevent the virus from entering cells.
  5. Prevent the virus from replicating in cells.
  6. Limit the side effects associated with the body’s inflammatory response.

Limit the virus presence in the environment.

Controlling the infection depends partly on our ability to limit contamination of the environment by the virus. This measure has not been the subject of clinical studies per se, but we have seen images from many countries around the world of workers spraying chemicals in the streets of cities. The spray solution is usually an inexpensive mixture of bleach and water (sodium hypochlorite). Its effectiveness is not guaranteed [4], and using it is not without danger to the public (or the person spraying it), especially if other antiseptic products are added.

Prevent the virus from reaching the respiratory tract.

Since the virus can only travel a very short distance through the air (other than via coughing and sneezing), it is definitely preferable to disinfect surfaces that may be contaminated with droplets from the respiratory tracts of infected individuals, who often have few or no symptoms. We all know the instructions: wash your hands frequently with soap (preferably) or an alcohol solution diluted in water, disinfect potentially contaminated surfaces and objects, wear a mask, maintain physical distancing, etc.

Read more: Sleep apnea: why microdroplets are likely to spread further into the room and remain suspended in the air for longer periods of time.

Destroy the virus once it enters the body.

Once the virus is in the body, can it be eliminated? Home remedies include gargling with mouthwash, eating garlic, rinsing your nose with saline, taking sesame oil and sunbathing. All of these myths had to be debunked by the WHO [5]. The Lysol company has even issued a warning to consumers against injecting themselves with disinfectants [6].

The best approach to preventing infection before the virus does damage is to mobilize antibodies. That is how you cure an infection. This is the principle behind the development of a SARS-CoV-2 vaccine [7] and the concept of herd immunity. This immunity depends on a large part the population developing antibodies that prevent the virus from spreading. However, the WHO has expressed serious concerns regarding how long this immunity actually lasts.[8]

If we cannot rely on a vaccine, could we at least use the antibodies produced by patients who have recovered? This technique, called “convalescent plasma,” has been known for about a century. It is currently the subject of a major clinical research project in Canada called “CONCOR,” which involves the Sainte-Justine Hospital in Montreal.[3]

However, the amount of convalescent plasma available is not sufficient to meet the needs of all patients. As a result, pharmaceutical companies have taken up the challenge of producing antibodies to COVID-19 in “industrial” quantities. The technique they are using is based on the production of identical antibodies called “monoclonal antibodies.” It includes the following steps:

  • Discover, in convalescent plasma, the structure of the most effective antibodies against the virus.
  • Manufacture strands of DNA that replicate this structure and introduce them into special cells (mouse hybridomas or genetically modified plants [9]).
  • Recover the antibodies produced by the cells.

Read more: Vaccine against COVID-19: Why does it take so long?

Prevent the virus from entering cells.

What should we do once the virus is in the respiratory tract? Prevent it from entering the cells of the lungs. SARS-CoV-2 does not easily enter all the cells of the body. Most of us have seen the virus depicted as a sphere covered with little spikes. A protein that forms these spikes, the “S protein,” has a strong affinity for the ACE2 receptor, a protein found on the surface of many cells. Contact between the S protein and the ACE2 receptor enables the virus to enter the cell. Several types of cells have ACE2 receptors on their surface and are therefore potential entry sites for the virus.

Canadian and Swedish researchers have succeeded in synthesizing proteins that can mask the S protein and thereby close the door to the virus. [10] A drug of this type called “APN01” is currently undergoing a clinical study in Europe [11].

Prevent the virus from replicating in cells.

Once the virus penetrates the cell, it sets the entire machinery of the cell in motion to reproduce. In humans, the information that enables SARS-CoV-2 to replicate is contained in a “chromosome” made up of ribonucleic acid (RNA) rather than DNA. To reproduce, the virus must first make a copy of its RNA chromosome in the form of DNA. This action, carried out by an enzyme called RNA polymerase, is one of the most important targets to prevent the virus from replicating. One of the drugs known to block RNA polymerase is remdesivir, a broad-spectrum antiviral agent already used in the fight against Ebola.[12] In the United States, a clinical study has shown that remdesivir can prevent SARS-CoV-2 from replicating, thereby reducing recovery time by 30%. Its use is already approved by the FDA for emergency prescriptions. [12]

Several other stages in the replication of the virus are also potential avenues for the development of a new drug, hence the use of a number of antiviral agents prescribed alone or in combination (ribavirin, lopinavir, ritonavir).

Limit the side effects associated with the body’s inflammatory response

The especially high mortality rate among the elderly appears to be due to an overly aggressive inflammatory response called a “cytokine storm.” The inflammatory response is essential for fighting infection and destroying the offending pathogen. To do this, millions of white blood cells are sent to the site of the infection, where they release various chemical compounds, including cytokines that can kill infected cells. In too great a concentration, the cytokines indiscriminately kill both healthy and infected cells. This destruction of healthy lung cells is believed to cause the complications of COVID-19.

A number of drugs already used to control the inflammatory response in certain conditions are being studied around the world. These include chloroquine and hydroxychloroquine, two drugs used to treat malaria. [13] This is also the case with colchicine, a drug that has long been used to treat gout and, in recent years, certain inflammations of the heart. The Montreal Heart Institute has launched a clinical research project on the use of this inexpensive drug to treat the complications of COVID-19. [14]

In conclusion

Many candidates, few winners? It is very likely that a single drug will not be sufficient to effectively treat COVID-19. We will probably need a combination of antibodies, antiviral agents and other drugs to calm the cytokine storm. As a result, we hope that by the time a vaccine is available, the numerous research projects currently underway will lead to effective, inexpensive and widely available treatment protocols.

Biron offers molecular PCR testing and serological test for COVID-19. Offered to individuals who do not present symptoms related to COVID-19, those tests must be prescribed by a physician. For more details, click here.

  1. “COVID-19 : la recherche clinique internationale connaît un dynamisme inédit,” https://www.univadis.fr/viewarticle/covid-19-la-recherche-clinique-internationale-connait-un-dynamisme-inedit-716825 (accessed May 15, 2020).
  2. Government of Canada, “Drugs and vaccines for COVID-19: List of authorized clinical trials,” https://www.canada.ca/en/health-canada/services/drugs-health-products/covid19-clinical-trials/list-authorized-trials.html (accessed May 15, 2020).
  3. Gouvernement du Québec, “Essais cliniques sur le SARS-CoV-2/COVID-19 actuellement réalisés au Québec,” https://msss.gouv.qc.ca/professionnels/documents/coronavirus-2019-ncov/Liste_essais_cliniques.pdf (accessed May 15, 2020).
  4. Valérie Borde, “Désinfecter les lieux publics?” Le Soleil [Quebec City], April 4, 2020, https://www.lesoleil.com/actualite/vos-questions-sur-la-covid-19/desinfecter-les-lieux-publics-a4d18e1ecbb34b4f0d56000a7cf8dc06 (accessed May 15, 2020).
  5. Alice Chantal Tchandem Kamgang, “COVID-19 : l’alcool ne vous protège pas, les moustiques ne la transmettent pas,” Radio-Canada, https://www.rcinet.ca/fr/2020/04/08/covid-19-alcool-protege-moustiques-transmettent/ (accessed May 15, 2020).
  6. Lysol Canada, “Coronavirus: Information on 2019 Novel Coronavirus and helpful tips,” https://www.lysol.ca/en/ (accessed May 15, 2020).
  7. Nicolas Tétreault, “Vaccine against COVID-19: Why does it take so long?” https://www.biron.com/en/news/science/vaccine-against-covid-19-why-does-it-take-so-long/ (accessed May 15, 2020).
  8. “Rien ne garantit encore que les personnes guéries sont immunisées, avertit l’OMS,” https://ici.radio-canada.ca/nouvelle/1697351/pandemie-infection-guerison-maladie-contagion-epidemie (accessed May 15, 2020).
  9. Pauline Gravel, “Des traitements développés à partir d’anticorps,” Le Devoir [Montreal], March 19, 2020, https://www.ledevoir.com/societe/science/575256/un-traitement-quebecois-developpe-a-partir-d-anticorps (accessed May 15, 2020).
  10. “COVID-19 : Le candidat médicament qui ferme la porte au virus,” https://www.santelog.com/actualites/covid-19-le-candidat-medicament-qui-ferme-la-porte-au-virus (accessed May 15, 2020).
  11. Floriane Valdayron, “Un médicament pourrait bloquer le SARS-CoV-2 avant qu’il n’infecte les cellules,” https://www.pourquoidocteur.fr/Articles/Question-d-actu/32033-Un-medicament-pourrait-bloquer-SARS-CoV-2-qu-il-n-infecte-cellules (accessed May 15, 2020).
  12. “Le remdesivir, un médicament qui aide les patients à se rétablir du COVID-19,” https://www.science.lu/fr/le-remdesivir-un-medicament-qui-aide-les-patients-se-retablir-du-covid-19 (accessed May 15, 2020).
  13. Julie Charpentrat, “Chloroquine, hydroxychloroquine et COVID-19 : où en est-on?” Le Soleil [Quebec City], March 26, 2020, https://www.lesoleil.com/actualite/science/chloroquine-hydroxychloroquine-et-covid-19-ou-en-est-on--07ec60e705f14d6730ec8e5bc1a2f6fe (accessed May 15, 2020).
  14. Philippe Mercure, “Des chercheurs québécois testeront un médicament contre les complications graves,” La Presse [Montreal], March 22, 2020, https://www.lapresse.ca/covid-19/202003/22/01-5265931-des-chercheurs-quebecois-testeront-un-medicament-contre-les-complications-graves.php (accessed May 15, 2020).