Washington University Scientists (WashU) believe using cannabis increases the likelihood of hospitalization if you catch COVID-19, that's according to the results of a new study. As patients sought treatment for COVID in local health centers, they were asked a simple yes or no question, “have you used cannabis in the past year?” 

“That gave us enough information to establish that if you use cannabis, your health care journey will be different,” said Nicholas Griffith, MD, a medical resident at WashU. “We can’t know how much cannabis you have to use, or whether it makes a difference whether you smoke it or eat edibles.” Griffith hopes answers will come with more research and studies. 

Among the patients who said "yes" to cannabis usage, 80% were more likely to be hospitalized and 27% were more likely to be admitted to the ICU than people who said "no." Tobacco smokers suffering from covid were 72% more likely to be hospitalized and 22% more likely to go to the ICU than nonsmokers. 

Researchers studied 72,501 people’s health records from BJC HealthCare hospitals and clinics in Missouri and Illinois during the first two years of the pandemic. Those that confirmed cannabis usage were significantly more likely to need hospitalization, according to researchers. 

“There’s this sense among the public that cannabis is safe to use, that it’s not as bad for your health as smoking or drinking, that it may even be good for you,” said Li-Shiun Chen, MD, DSc, a professor of psychiatry. “I think that’s because there hasn’t been as much research on the health effects of cannabis as compared to tobacco or alcohol. What we found is that cannabis use is not harmless in the context of COVID-19. People who reported yes to current cannabis use, at any frequency, were more likely to require hospitalization and intensive care than those who did not use cannabis.”

“The results contradict some other research suggesting that cannabis may help the body fight off viral diseases such as COVID-19,” wrote WashU Senior Medical Science writer Tamara Schneider. She explained the study wasn’t meant to answer why cannabis use might make COVID-19 worse, though, “one possibility is that inhaling marijuana smoke injures delicate lung tissue and makes it more vulnerable to infection – it is also possible that cannabis, which is known to suppress the immune system, undermines the body’s ability to fight off viral infections no matter how it is consumed, the researchers noted.”

You can read more about the study, published in the June 21 JAMA Network Open.