This brief review of the literature assesses how the anti-inflammatory effects of cannabinoids affect the body’s ability to fight off viral infections. The results were mixed, showing that in cases of immunopathology (when the immune system’s response is what is causing the symptoms), cannabinoids improve the ability to fight off viruses.
Here is the full scientific article if you wish to download it.
However, in all other studied cases, the profound anti-inflammatory effects of cannabinoids were so powerful they downregulated the immune system so effectively that the virus was able to spread and infect more cells and tissues.
The mechanism by which cannabinoids can exert this effect is discussed, particularly the Ca2+ signalling pathways that are mediated by the cannabinoids receptor type 1 (CB1). This adds to our understanding of the endocannabinoid system, the immune system, how viruses interact with the body, and the potential uses of cannabinoid in therapy.
Inflammation is one of the ways the body fights off viral infections. It is a complex and not fully understood the process. One very important element of the inflammatory response is the Ca2+ dependent enzymes. It is important in many of the stages of inflammation, from the initial innate response to the adaptive immune cell response.
When a virus infects the body, the first line of defence is the innate immune system. It fights to stop the virus from spreading or infecting too many cells until the adaptive immune system can learn to recognize the cells. It is an exquisitely precise system that is partially mediated by the endocannabinoid system, or the receptors and enzymes that cannabinoids affect.
For the many different types of viral infection studied, almost all showed an increase in virus success, recovery times, damage done by the viruses, and infectiousness. By downregulating the immune system via CB1 – Ca2+ interactions, cannabinoids reduce the body’s ability to fight off infections. Both inflammatory and cell-autonomous (the cell doing it by itself) antiviral responses were demonstrably worsened in most cases.
When a viral infection causes the immune system to damage the body, this downregulating of the inflammatory and cell-autonomous viral responses was useful, however. By tuning down the immune response, inflammation and damage by immune proteins called cytokines were significantly reduced, resulting in fewer symptoms and improved recovery. This was only true for a small number of viruses.
While this is revealing of the endocannabinoid system’s role in inflammation and viral response, it does suggest that regular cannabis use during infection should be avoided
Although the data are usually from small-scale studies and are of sometimes surprisingly poor quality, they do suggest that recreationally ingesting cannabinoids can significantly impair the body’s ability to fight off viral infections. In herpes and HIV, people (and guinea pigs) who took cannabis regularly were found to suffer from worse symptoms and morbidity.
A similar effect was demonstrated for bacterial infections. This is hardly surprising: the initial response to viruses and bacteria often involve the same systems. Syphilis, legionnaires disease, and tuberculosis infections were all found to be exacerbated by THC consumption.
Although cannabinoids have many positive medicinal effects, this paper quite convincingly proves that in most cases, ingesting cannabinoids when infected with a virus will significantly impair the body’s ability to fight it.