TORONTO -- Two researchers in Alberta believe new strains of cannabis could potentially prevent the most fatal respiratory effects of COVID-19 and maybe even block the virus from entering the body at all.

The husband and wife team of Drs. Igor and Olga Kovalchuk at the University of Lethbridge have been studying the use of new strains of cannabis to fight cancer and inflammation. When the pandemic struck, they turned their attention to the novel coronavirus.

They hoped to find strains of cannabis that would interfere with the virus’ ability infiltrate the body by hijacking special proteins or receptors. One of the receptors, known as ACE2, has previously been determined to be a key doorway for the COVID-19 virus to enter the body.

The Kovalchuks believe certain cannabis strains can work in two ways – blocking the virus from gaining entry to the body in the first place, and preventing its propagation if it’s already in a person’s system.

Their research has found certain cannabis strains show the potential to control an immune system that’s gone into overdrive in COVID-19 patients. When that happens – the dreaded cytokine storm – the immune system starts attacking the body itself. That can lead to acute respiratory distress syndrome (ARDS) and the need for the patient to be placed on a ventilator.

Igor Kovalchuk says their lab has developed more than 1,500 hybrid strains of cannabis over the last five years and have tested about 400 of them against the SARS-CoV-2 virus that causes COVID-19.

So far, they have found about a dozen that are able to “substantially decrease the expression of the ACE2 receptor, the one that is required by the virus to enter our cells,” he told CTV’s Your Morning Friday.

Two or three strains developed in the Kovalchuks’ lab and tested on human tissue models can decrease that receptor’s acceptance of the virus – essentially closing the door to infection – by 75 per cent or more, said Igor Kovalchuk. That gives the body a much better chance of fighting the viral invader.

Strains the scientists are working with are cannabidiol (CBD)-predominant. That means they have high presence of the medicinal ingredient of cannabis and relatively little of the tetrahydrocannabinol (THC), which is the psychoactive component of cannabis that causes a high.

Igor Kovalchuk says it’s generally recommended that THC dosage be limited to 25 mg a day to prevent impairment, so the strains they are studying as potential answers for COVID-19 would allow a dose of 500 mg of CBD without hitting that limit.

Cannabis has a good safety profile and often can improve quality of life through reducing anxiety, improving sleep and boosting appetite, says Olga Kovalchuk.

The couple’s work was published as a preliminary report in a May issue of the online medical journal Research Square. It is undergoing peer review. https://www.researchsquare.com/article/rs-30927/v1

The next big step is real-world testing of the cannabis strains that have performed well in the lab, says Olga Kovalchuk.

“Right now, what’s most important for us is to actually find partnerships and develop clinical trials.”

The Kovalchuks, both professors in University of Lethbridge’s Department of Biological Sciences, are working in partnership with Pathway RX, a company founded and headed by Igor Kovalchuk that is focused on developing custom cannabis therapies.

The hope is to eventually develop medical formulations inhalers, mouthwash and gargling products that could be used to prevent and treat COVID-19.

The researchers have not tested smoking cannabis and say none of the strains they are studying are available for sale at local cannabis shops.