Cannabinoids, Influenza, and Coronavirus

With everything happening in the news lately, we want to present some scientific data to help medical cannabis patients and adult-use consumers make informed decisions in regard to cannabis products available, product safety, and personal health. Each person’s health situation is unique, and medical cannabis patients should discuss with their doctor or healthcare provider the best approach to prevent and treat current illnesses while potentially battling influenza or coronavirus.

What is the influenza virus? 

The influenza virus is an RNA-virus whose genera includes Influenza A, Influenza B, and Influenza C. RNA, which stands for ribonucleic acid, is present in all living cells and acts as a messenger from DNA that controls the synthesis of various proteins in the body. Why is this important? Instead of the body producing proteins needed for normal functioning, the RNA replicates the virus, causing the viral load inside the body to increase.

Figure 1: Molecular Structure of Influenza Virus
Figure 1: Molecular Structure of Influenza Virus1

What is the coronavirus?

The coronavirus is also a class of RNA-viruses that replicates rapidly, and includes Sudden Acute Respiratory Syndrome (SARS) and Middle Eastern Respiratory Syndrome (MERS).2 It is called a coronavirus because of the crown-like spikes3 that extrude from the virus, as shown in Figure 2. However, the structure of the flu virus is noticeably different in that the spikes that protrude from the cell are the same height as the membrane proteins, whereas in the coronavirus the protein spikes are higher than the membrane proteins. Why is this structural difference important? Simply put, it makes the coronavirus harder to treat and it makes traditional flu vaccines ineffective.

Figure 2: Molecular Structure of Coronavirus
Figure 2: Molecular Structure of Coronavirus4

Cannabis and the Immune System

In the endocannabinoid system, cannabinoids and terpenes interact with both the CB1 and CB2 receptors, as well as other receptors. While both CB1 and CB2 receptors are present in the central nervous system (CNS) and the peripheral nervous system (PNS), CB2 receptors are more heavily located in immunomodulatory cells. The immune system plays a key role in helping people stay healthy by performing a number of different functions through various molecular pathways. 

In 2008, Buchweitz et al. reported the effects of THC on mice infected with the influenza virus and noted that the immune system experienced increased viral loads and suppressed lymphocyte production.5 A follow-up study reported by Karmaus et al., appears to support the initial data that THC may suppress the immune system and cause increased viral load.6 It should be noted however, that these were small studies conducted on mice, where cannabinoids were ingested, and have been hard to replicate.

Immune system suppression is only one potential outcome of the consumption of THC. Many patients with HIV/AIDS or those who are suffering from cachexia or chemotherapy-related nausea, who have compromised immune systems, are recommended THC to alleviate these devastating side effects. THC also shows promise in treating inflammatory responses to multiple sclerosis and amyotrophic lateral sclerosis.7 Lunn, et al., note that CBD has well-documented anti-inflammatory properties and that it may inhibit immune cell migration through CB2 receptor activation,8 and studies on the entourage effect have shown addition of CBD to potentially change the outcome of THC activity. 

Patient Recommendations 

What can be seen from this lack of conclusive scientific data, is that each medical cannabis patient must take into account their own personal needs and their own personal situation. If patients have found a particular product that works well for them, they should continue to take their medication as recommended by their physician. If a patient is experiencing the flu, coronavirus, or other types of respiratory illness, they should consult with their physician to determine what changes may need to be made to their medications. This may include switching from an inhalation type of medicating (i.e., smoking/vaping) to an oral medication (i.e., edibles, lozenges, oil extracts, etc.).

Patients are also encouraged to follow all recommendations from the Centers for Disease Control and Prevention’s guidelines to prevent the spread of illness and follow good sanitation practices. Many states with medical cannabis programs have put into place good production and sanitation practices to help ensure that the products being sold meet health and safety requirements. Consumers should ensure that the products that they are purchasing have been cultivated and manufactured in a manner consistent with health and safety requirements. The Patient’s Guide to CBD, which reviews best practices and discusses how to read a certificate of analysis, is a good resource for those wanting to learn more.

Americans for Safe Access has also developed a series of COVID-19 policy recommendations for Governors and medical cannabis program heads, which you can review and support online. ASA also encourages patients and advocates to share descriptions of the COVID-19 responses impacting their local cannabis businesses and their implications for patients. We have created a central hub for sharing those experiences.



  2. Masters, P.S. (2006) The Molecular Biology of Coronaviruses. Advances in Virus Research, 66:193-292.
  4. Holmes, K.V. (2003) SARS-Associated Coronavirus. New England Journal of Medicine, 348(20):1948-1951.
  5. Buchweitz, J.P., et al. (2008) Targeted deletion of cannabinoid receptors CB1 and CB2 produced enhanced inflammatory responses to influenza A/PR/8/34 in the absence and presence of 𝚫9-tetrahydrocannabinol. Journal of Leukocyte Biology, 83(3):785-796.
  6. Karmaus, P.W., et al. (2013) 𝚫9-Tetrahydrocannabinol Impairs the Inflammatory Response to influenza Infection: Role of Antigen-Presenting Cells and the Cannabinoid Receptors 1 and 2. Toxicological Sciences, 131(2):419-433.
  7. Pertwee, R.G. (2008) The diverse CB1 and CB2 receptor pharmacology of three plant cannabinoids: 𝚫9-tetrahydrocannabinol, cannabidiol, and 𝚫9-tetrahydrocannabivarin. British Journal of Pharmacology, 153:199-215.
  8. Lunn, C.A., et al. (2006) A novel cannabinoid peripheral cannabinoid receptor-selective inverse agonist blocks leukocyte recruitment in vivo. Journal of Pharmacological Experimental Theories, 316:780-788.