CBD Stops Covid-19 From Replicating in Human Cells, Lab Study Finds
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CBD and its metabolite 7-OH-CBD can effectively block the viral replication of coronavirus (SARS-CoV-2) in mice and in human lung cells, according to new research from an interdisciplinary team of scientists at the University of Chicago.
Published in Science Advances, the researchers also found a significant negative association between CBD and positive SARS-CoV-2 tests reported in a national sample of medical records for patients taking FDA-approved CBD formulations to treat epilepsy.
In light of these observations, the researchers say that clinical trials must be done to determine whether CBD could eventually be used as a preventative or early treatment for Covid-19 and SARS-CoV-2 infection. Identifying other therapeutic treatments for Covid-19 is a high priority for scientists given the emergence of new variants and the number of people who currently lack access to vaccines.
However, the scientists do also caution that these effects only come from high-purity CBD formulations taken at certain times, and do not suggest that commercially-available CBD products can prevent Covid-19.
CBD for Covid
The researchers studied CBD alongside a range of other closely related cannabinoids, including THC, CBDA, CBDV, CBC, and CBG. Each of the cannabinoids was applied to a sample of human lung carcinoma cells for two hours before the cells were infected with the SARS-CoV-2 virus and monitored for the virus and viral spike protein.
“CBD has anti-inflammatory effects, so we thought that maybe it would stop the second phase of Covid infection involving the immune system, the so-called ‘cytokine storm.’ Surprisingly, it directly inhibited viral replication in lung cells,” senior study author Marsha Rosner, a professor in the Ben May Department of Cancer Research, said in a statement.
They found that CBD and its metabolite 7-OH-CBD inhibited the virus’ ability to replicate for up to six hours after it had infected a cell. This held true when the test was repeated using a different human lung cell line and monkey kidney cells, as well as when tested against the alpha, beta, and gamma SARS-CoV-2 variants. Notably, co-administration of CBD with THC significantly suppressed CBD’s positive effect.
“We just wanted to know if CBD would affect the immune system,” Rosner said. “No one in their right mind would have ever thought that it blocked viral replication, but that’s what it did.”
When a virus infects a host cell, it encodes a limited number of viral proteins which are able to interact with the cell’s RNA-binding proteins. By doing this, the virus essentially hijacks the cell’s gene expression machinery and begins to produce even more copies of itself and the viral proteins that can spread to more cells and ultimately cause disease.
When tracking the virus-induced changes in cellular RNAs, researchers also observed that CBD almost entirely eradicated the expression of viral RNAs. Both CBD and SARS-CoV-2 also induced their own unique changes in cellular gene expression, but in cells treated with CBD and SARS-CoV-2 the viral changes had been almost completely reversed with the administration of CBD. These cells instead resembled those treated with CBD alone.
Patients taking CBD test positive for Covid-19 at lower rates
Widening the scope of this research beyond the laboratory, the researchers also analyzed 1,212 patient data records taken from the National Covid Cohort Collaborative. They found that patients taking a prescribed oral solution of CBD for treating epilepsy reported testing positive for Covid-19 at significantly lower rates than a comparable population who did not use CBD.
“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,” said Rosner. “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.”
While this real-world data does appear to back up CBD’s potential as a way to combat coronavirus replication, the scientists behind the study continue to urge caution until appropriate clinical trials can be done. The potential benefits of CBD do not surpass the existing public health advice in place to wear face masks, regularly wash hands, get vaccinated, and follow social distancing where directed.
Additionally, while this research does highlight a promising avenue for future development, the results do not extend to commercially available CBD products.
“Going to your corner bakery and buying some CBD muffins or gummy bears probably won’t do anything,” said Rosner.
“The commercially available CBD powder we looked at, which was off the shelf and something you could order online, was sometimes surprisingly of high purity but also of inconsistent quality,” Rosner added. “It is also hard to get into an oral solution that can be absorbed without the special, FDA-approved formulation.”
Cannabinoids and the coronavirus
In light of the promising experimental results and real-world data patterns uncovered by this study, the scientists behind it are calling out for clinical studies to fully evaluate the usefulness of CBD as a preventative treatment for the SARS-CoV-2 virus. Additional studies should also seek to determine ideal dosing regimens and identify any potential side effects when CBD formulations are used for this purpose.
“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.”
Other cannabinoid research projects relative to Covid-19 are also underway. Recent findings from researchers at Oregon State University suggest that the acidic cannabinoids CBDA and CBGA may prevent infection by binding to the SARS-CoV-2 spike proteins and hampering the virus’ ability to enter cells in the first place.
The UK Medicines and Healthcare Regulatory Agency (MHRA) also recently announced that it has approved a new six-month clinical trial to investigate the effects of medical cannabis on long Covid.
Long Covid is the term given to the symptoms that persist for weeks and months after the initial Covid-19 disease has passed. This often includes debilitating fatigue, an irregular heartbeat, shortness of breath, chest and joint pain, a continuous cough, and the autoimmune condition Sjögren's syndrome, which causes chronically dry eyes and a dry mouth.
The new clinical trial will be conducted within the UK by the independent scientific body Drug Science UK, with patient recruitment already underway.