CBD May Prevent COVID-19 Infection but Don't Start Popping Gummies Just Yet

Cannabis may come to the rescue during the coronavirus health pandemic, new research suggests. But smoking marijuana joints or hitting that vaporizer will not save you from COVID-19.

Neither will CBD-laced gummy candy from the local weed dispensary.

But chemical compounds inside the cannabis plant, only the hemp-derived CBD though not THC-laden marijuana, could be effective in preventing COVID-19 infections, according to a team of researchers at the University of Chicago.

The Chicago study, published in Science Advances, is the first and only study of its kind to test on animals. Research data shows that cannabidiol can possibly prevent COVID-19 infections.

When tested in mice, researchers saw a few significant findings: CBD blocked the virus from replicating, and pretreatment with CBD lowered the amount of the virus in the lungs and nasal passages.

CBD is one of the two most commonly known compounds derived from the cannabis plant and found in marijuana. CBD is not a psychoactive drug, unlike the popular compound Tetrahydrocannabinol (THC), which is the chemical that gets people high.

"We think it (CBD) has potential to be preventative or decrease the effects of the virus," said researcher Marsha Rosner, the Chicago study's senior author. "We don't know yet if CBD can prevent COVID, but our results provide a strong case for conducting a clinical trial."

Similar studies, including one published by Oregon researchers earlier this month, have found potential benefits in using cannabis compounds against COVID-19.

The University of Chicago study — titled "Cannabidiol inhibits SARS-CoV-2 replication through induction of the host ER stress and innate immune responses" — found CBD to be an effective COVID blocker under highly specific conditions.

So why shouldn't you go out and buy CBD products to consume?

It's an issue of purity, researchers said. The Chicago study used a CBD compound that was 98 percent pure.

"It's almost completely pure (CBD)," Rosner said.

That incredibly high level of purity is not on the shelves of retail dispensaries, she said.

The U.S. Food and Drug Administration approved Epidiolex, a cannabidiol oral solution, in 2018. But that prescription medication is used for the treatment of seizures associated with two rare and severe forms of epilepsy, Lennox-Gastaut syndrome, and Dravet syndrome.

Commercial compounds that you can find in the form of gummies, oils, or supplements vary heavily in quality and have a much lower percentage of CBD.

There are still a lot of unknowns about the health benefits of CBD and its effectiveness in preventing COVID-19, Rosner said, because it has yet to be studied in humans.

But there are signs it may be successful. One analysis included 1,212 people from the National COVID Cohort Collaborative who took Epidiolex. Those who took the CBD medication tested positive for COVID-19 at much lower rates compared to others who did not consistently take the drug.

"It's promising. It has potential. But we really need a clinical trial,'" Rosner said.

CBD has the potential to prevent infection, similar to the COVID-19 vaccine, but the medication would work in different ways.

The mRNA vaccine, which includes Moderna and Pfizer, prevents infection by creating proteins that mimic the virus to trigger the immune response, which produces antibodies. Those antibodies then coat the SARS-CoV-2 virus and block it from infecting cells.

"I would argue that's much more effective than any of the CBD-related products that we could have that might have an effect," Rosner said.

CBD takes advantage of the body's natural immune response using the interferon signaling pathway.

Interferons are a group of proteins that signal infection when the body is exposed to pathogens, such as COVID-19.

"The interferon signaling pathway comes back and acts to break down the virus and basically cause it to go away — if you're lucky," Rosner said.

While Rosner is hopeful the lab-rat test results are true for humans, and CBD can actually prevent infection, it still shouldn't be seen as a substitute for the vaccine.

"I would view CBD as an extra protection to vaccines" if successful in clinical trials, Rosner said. "Something we can take to avoid general kinds of infections."

Rosner and her University of Chicago colleagues were not the first to experiment with cannabis compounds and SARS-CoV-2, but they were the first to test in mammals.

"There is just so much to uncover before any human translatability is suggested, including underscoring the importance of understanding the safety of ingesting these cannabinoids at different amounts with varying routes of administration," she said.

A study conducted by researchers at two Oregon universities — titled "Cannabinoids Block Cellular Entry of SARS-CoV-2 and the Emerging Variants" — made waves when it was published on January 10.

Researchers found three cannabis compounds — CBGA, CBDA, and THCA — blocked the virus from entering and infecting the cell.

"There are a number of compounds that work in cell culture, but they don't work in animals," Rosner said. "So you have to do it under physiological conditions."

In this case, those physiological conditions required a much smaller dosage of the tested compound.

"What we found in our study is that the compounds CBGA, CDBA, even THC … had no effect at blocking the virus at the doses that we were using," Rosner said. "You need to get it into the body at a level that it will be effective in the cells in your body. And it turns out that all of these compounds are not very soluble in water, so they get broken down in the liver. So it's really hard to get high levels of the compound in your blood."

Marcel Bonn-Miller, a researcher who has focused on cannabis at the University of Pennsylvania and is vice president of human and animal research at Canopy Growth Corporation, also noted "the dangers of jumping to conclusions from early research."

"Studies conducted in petri dishes may have direct implications for the use of CBDA and/or CBGA via oral administration in humans to prevent or treat COVID-19 infection, although more research should be conducted before we accept that conclusion or apply the findings more broadly," Bonn-Miller said in an email regarding the Oregon study.

Richard van Breemen, the author of the study and professor of medicinal chemistry at Oregon State University, said in an email he was "pleased" the Chicago research "found that CBD can inhibit SARS-CoV-2 replication after cell entry" and agreed that clinical trials testing the efficacy of cannabinoids, or cannabis compounds, are necessary.

Rosner, a cancer biologist who pivoted to COVID-19 research as soon as it emerged, said she understands the excitement because "it's something that is accessible and genuinely not toxic."

Until a clinical trial can confirm CBD's efficacy in humans, she said there's no reason to rush to buy CBD products.