Could Antivirals Fight Coronavirus? What You Need to Know
Scientists and researchers around the world are working around the clock to find treatments and develop a vaccine for the novel coronavirus. As countries have begun to loosen restrictions in some places and return to business as usual, we are beginning to see another spike in new infections. That makes the race to find a treatment or develop a vaccine even more critical. Some early research indicates that new and existing antivirals could be used to help the body fight off COVID-19. How do these antivirals work, and why might they be effective against COVID-19 (or not)?
What Is an Antiviral?
Though creating a vaccine is important because it could stop people from ever becoming infected, finding effective antivirals is equally vital; these could help patients who already have the disease get better faster.
Antivirals have a long history of use against respiratory viruses, but unfortunately, the results have always been mixed. Hundreds of antivirals have been tested over the years, but very few have actually made it to market. Of the antivirals used to treat respiratory viruses that have made it, only a very few seem to make a difference, and even then, their impact on the death rate (an extremely important factor) seems to be quite small. Many existing antivirals are used against other illnesses, like cancers and HIV, and researchers have begun testing these existing antiviral drugs for use against COVID-19.
Antivirals Currently Being Tested
To understand how antivirals work, you must first understand the difference between animal and plant genomes (made up of deoxyribonucleic acid, or DNA) and viral genomes (often composed of ribonucleic acid, or RNA). An RNA virus needs to create copies of its RNA genome to reproduce — this is the case with the virus that causes COVID-19, SARS-CoV-2. Antiviral drugs that can block this copying of the viral RNA genome could potentially be used to help patients recover once they have contracted COVID-19. These antivirals are known as RNA-polymerase inhibitors, and they have been used to fight other similar RNA virus infections, like hepatitis C. One such drug currently in trials for use against COVID-19 is favilavir.
Another common type of antiviral works by creating analogues, or copies of the basic components of the RNA genome, in the virus. These non-functional analogues block the virus’s ability to make copies of its RNA genome. There are a few drugs that work in this way, but unfortunately, this particular coronavirus can identify inauthentic analogues and remove them before they can do their job of stopping the copying of the RNA genome. However, at least one drug, remdesivir, has not been blocked by the novel coronavirus — it is currently showing promise in clinical trials against COVID-19.
Other Common Antivirals
Viral protease inhibitor drugs are another common version of antivirals that have been used with some success against diseases like HIV and hepatitis C. These drugs block proteases, which are enzymes within an RNA virus that are used to break down multi-proteins into individual proteins. One such viral protease inhibitor is called Kaletra, and it is being studied for its effectiveness against coronavirus, though early trials have not been promising.
The Earlier the Better
Antivirals are really only useful when administered as early as possible. Many common antivirals (like Tamiflu) that are used to fight influenza are usually only administered on the first day or two of the virus’s onset. Because viruses reproduce so quickly, antivirals simply don’t work as well in the later stages.
This early administration of antivirals is also important because as the disease progresses, the second stage large-scale inflammatory response might not be affected by the use of antivirals. This second phase of COVID-19, and perhaps a more deadly component, is known as a cytokine storm. A cytokine storm occurs when the body’s immune response kicks into overdrive; it’s fighting off the virus, but the inflammation that results from this process can be just as deadly, or even more so, than the virus itself.
To fight off a cytokine storm in COVID-19 patients, researchers have begun to test drugs that suppress the immune system. For obvious reasons, these should not be used in the early stages of the virus, but they may help calm the overreacting immune system associated with the later stages of COVID-19.
More Research Ahead
Researchers have a lot of work ahead of them in the fight against the novel coronavirus. All over the world, the race is on to develop effective treatments and a working and safe vaccine. There are more than 3,500 trials underway currently across the globe, and somewhere around 254 potential treatments currently undergoing development. Hopefully, researchers can soon find a winning combination.
