By Julia Marnin, McClatchy Washington Bureau
One active ingredient in the cannabis plant — cannabidiol (CBD) — could potentially block COVID-19 infection, a new study suggests.
If you’re wondering if this means you’ll be protected from the virus by smoking weed or vaping CBD, the answer is no. Here’s what the research means:
You might have seen products with the non-psychoactive marijuana compound legally sold in stores and advertised with potential calming capabilities. However, the commercially available CBD that can be infused in food or drinks isn’t of the same quality as the CBD used in the study, authors point out in the peer-reviewed research published Jan. 20 in Science Advances.
A review of 1,212 U.S. patients prescribed an oral, high-purity CBD dose of 100 milligrams-per-millilitre showed they tested positive for COVID-19 at lower rates compared to matched control groups of patients who didn’t take CBD, according to the 33 researchers from the University of Chicago, University of Louisville, University of Illinois at Chicago and the National COVID Cohort Collaborative Consortium.
The study’s findings suggest CBD, specifically derived from the cannabis sativa plant, can be used as a “potential preventative agent” for early COVID-19 infection and warrants further research.
“A clinical trial is necessary to determine whether CBD is really effective at preventing or suppressing SARS-CoV-2 infection, but we think this may have potential as a prophylactic treatment,” Dr. Marsha Rosner, who is one of the study’s lead researchers and a professor at the University of Chicago, said in a news release. “Maybe you’re in a hot spot or you think you might have been exposed or you’ve just tested positive —that’s where we think CBD might have an effect.”
READ MORE: New research suggests CBD might help prime cells against COVID-19
A survey of patients prescribed CBD
In the study, records of 1,212 patients who had a “history of seizure-related conditions” and were prescribed 100mg/mL of CBD were examined, researchers wrote, pointing out how CBD “is often used for the treatment of seizures.”
They found that 75 patients — 6.2 per cent — tested positive for COVID-19 compared with 8.9 per cent of control group patients who didn’t use CBD but also had a history of seizure-related conditions.
Then, they further examined 531 CBD-prescribed patients out of the entire group that were likely already taking the concentrated dose the day they were first tested for COVID-19, according to the study.
Out of this sub-group, just 4.9 per cent tested positive for COVID-19 compared with 9 per cent of 531 patients in a matched control group that didn’t take CBD.
These results revealed a link between the highly concentrated CBD doses and “substantially fewer SARS-CoV-2 positive test results,” researchers wrote.
They caution against self-treating with “non-medical” CBD “edibles, inhalants or topicals as a preventative or treatment therapy at the present time.”
“Going to your corner bakery and buying some CBD muffins or gummy bears probably won’t do anything,” Rosner said in the news release.
READ MORE: University of Toronto researcher looks at cannabinoids to treat obesity
Other findings
Before researchers examined data on patients prescribed CBD, they conducted laboratory tests in human lung cells and in mice and found the marijuana ingredient “inhibits” COVID-19 infection.
“The researchers first treated human lung cells with a non-toxic dose of CBD for two hours before exposing the cells to the COVID virus and monitoring them for the virus and the viral spike protein,” the news release explains.
The cannabis ingredient prevented the virus from replicating in the cells, according to the study.
Then, researchers gave mice CBD one week before infecting them with the virus and found that it “suppressed infection both in the lung and the nasal passages of mice,” the release said.
The research contributes to a growing body of studies that examines potential benefits the cannabis plant can have when it comes to COVID-19 infection.
Prior to this CBD study, research from Oregon State University found that two other cannabis sativa plant compounds — CBGA and CBDA — could prevent COVID-19 from infecting human kidney cells in a peer-reviewed laboratory study published earlier in January.
The CBD study found that “closely related cannabinoids such as CBDA, CBDV and THC” actually “did not have the same power,” at preventing the virus, the news release noted. The psychoactive compound THC is likely the most familiar cannabis compound alongside CBD.
Although the studies’ findings differ in terms of the effectiveness of certain cannabis compounds, they both suggest more studies are needed.
“We are very eager to see some clinical trials on this subject get off the ground,” Rosner said. “Especially as we are seeing that the pandemic is still nowhere near the end — determining whether this generally safe, well-tolerated and non-psychoactive cannabinoid might have anti-viral effects against COVID-19 is of critical importance.”
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