The COVID-19 crisis seems to have created a tidal wave of misinformation and fake news about the role that cannabis has to play in the pandemic. Unphased by a complete lack of evidence, critics seem convinced that marijuana makes the virus more deadly, while others argue that it helps the immune system resist infection. Searching for the facts can be a bit like sniping for spliff butts at the end of a party, but if you search hard enough you’ll always find something useful.
To start with, there have been no studies on the interactions of cannabinoids with any of the viruses in the coronavirus family, so it’s impossible to say with any certainty what the consequences of cannabis use may be in the current situation. However, the more we learn about COVID-19, the more we can begin to speculate about how weed may help or hinder the body’s chances of remaining healthy.
For example, research has shown that the SARS-CoV2 virus (which causes coronavirus) triggers something called a cytokine storm, whereby infected cells release excessive levels of proteins called cytokines, resulting in hyperinflammation[i]. In light of the well-known anti-inflammatory properties of CBD, it has been suggested that cannabis may help to curtail this cytokine storm and thereby limit the damage caused by the virus. Previous studies have even shown that smoking cannabis reduces cytokine production in healthy adults[ii], though it is unknown whether or nor this would extend to people who had been infected with coronavirus.
Even if weed does limit the cytokine storm and reduce inflammation, it is unlikely that this alone would rid the body of coronavirus. In all probability, cannabis would need to be combined with steroid therapy in order to have any chance of defeating the virus – which is why scientists at the Rabin Medical Centre in Israel are now preparing to begin a small clinical trial using a combination of CBD and steroid therapy to treat hospitalised coronavirus patients[iii].
Other studies have shown that coronavirus infects cells by latching onto a protein called ACE2, which is found in lung tissue and in oral and nasal mucus. Medications that stop cells from producing this protein could therefore provide protection against infection, and researchers in Canada have found evidence that certain cannabis strains may actually produce this effect.
The team found that 13 different high-CBD strains all caused alterations to ACE2 levels in cultured human cells, leading them to conclude that “high CBD C. sativa lines, pending further investigation, may become a useful and safe addition to the treatment of COVID-19 as an adjunct therapy. They can be used to develop easy-to-use preventative treatments in the form of mouthwash and throat gargle products for both clinical and at-home use.”[iv]
However, the researchers also warn that some cannabis strains were ineffective, while others actually produced harmful molecular effects, so it’s important not to assume that all marijuana varieties can be of use in the fight against coronavirus. If anything, this research only highlights the need for more testing and analysis of different strains.
It’s also worth bearing in mind that tobacco smoke increases ACE2 levels and exacerbates the symptoms of coronavirus[v], suggesting that smoking cannabis with tobacco probably isn’t the safest way to ingest cannabis.
When it comes to high-THC strains, things look a little less promising. There’s precious little evidence regarding the impact of this cannabinoid on viral infections in humans, although one study found that it suppressed the immune response of mice that had been infected with a flu virus[vi],[vii].
All in all, we simply don’t know yet whether cannabis has a legitimate role to play in treating coronavirus, although high-CBD products that can be consumed without smoking currently seem to have the most potential. Until then, people will no doubt make up their own minds and continue to self-experiment, although it doesn’t take a scientist to work out that sharing joints is the last thing anyone should be doing right now.
[i] Kevin P. Hill.Cannabis and Cannabinoid Research.ahead of print http://doi.org/10.1089/can.2020.0035
[ii] Pacifici R, Zuccaro P, Pichini S, et al. Modulation of the Immune System in Cannabis Users. JAMA. 2003;289(15):1929–1931. doi:10.1001/jama.289.15.1929-a
[iv] Wang, B.; Kovalchuk, A.; Li, D.; Ilnytskyy, Y.; Kovalchuk, I.; Kovalchuk, O. In Search of Preventative Strategies: Novel Anti-Inflammatory High-CBD Cannabis Sativa Extracts Modulate ACE2 Expression in COVID-19 Gateway Tissues. Preprints 2020, 2020040315
[v] Brake SJ, Barnsley K, Lu W, McAlinden KD, Eapen MS, Sohal SS. Smoking Upregulates Angiotensin- Converting Enzyme-2 Receptor: A Potential Adhesion Site for Novel Coronavirus SARS-CoV-2 (Covid- 19). J Clin Med 2020; 9(3).
[vii] Reiss CS. Cannabinoids and viral infections. Pharmaceuticals (Basel) 2010;3:1873–1886.