Substance Use Disorders Increase Risk of COVID-19 Infection, Hospitalization, Even After Vaccination

By Lauren DeSouza- Master of Public Health, Simon Fraser Public Research University – Canada
Staff Research and Content Writer

This article is reproduced herein with permission of the copyright holder.

© Copyright – SUD RECOVERY CENTERS – A Division of Genesis Behavioral Services, Inc.,
Milwaukee, Wisconsin – December 2021 – All rights reserved.

10.8% of Americans live with a substance use disorder (SUD). SUDs include alcohol use disorder, cannabis use disorder, cocaine use disorder, opioid use disorder, and tobacco use disorder. Research has shown that those with SUDs are at a higher risk of contracting COVID-19, and now new research has concluded that this is true even when patients are vaccinated.

A new study compared the risks of “breakthrough” infections among vaccinated patients with and without SUDs. A breakthrough infection is when someone gets infected with COVID-19 even though they are fully vaccinated (World Health Organization). 

While vaccines are highly effective against COVID-19, some populations are still more vulnerable to infection even when vaccinated. Researchers are working to identify these populations to help make sure they are protected.

What did this study show?

This study compared the number of breakthrough COVID-19 infections among vaccinated patients with SUDs and without SUDs. The researchers found that those with SUDs had much higher rates of infection compared to those without SUDs. The highest rates of breakthrough infection were seen among those with cannabis use disorder and cocaine use disorder, at 7.7-7.8%, which is double the rate for those without SUDs (3.6%). 

The researchers concluded that those with SUDs are at a higher risk of a COVID-19 breakthrough infection than those without SUDs. 

This study also looked at the rates of hospitalization and death among those with breakthrough COVID infections. They found that 22% of vaccinated patients with SUDs were hospitalized, compared to 17.5% of vaccinated patients without SUDs. Those with SUDs also had a higher risk of death from their breakthrough COVID infection.

Why are breakthrough infections more common among people with substance use disorders?

People living with SUDs often have health conditions that make them more at risk for COVID-19. These can include various types of cancer, diabetes, liver disease, heart disease, and lung disease. As well, drugs and alcohol can weaken the immune system and harm other systems of the body, including the respiratory (breathing) system, which also increases the risk of COVID-19. 

Other factors that influence health include social and economic factors, for example being homeless or housing-insecure, having a lower level of education, or unemployment. People with SUDs often have more difficult social and economic situations, which contributes to a higher risk of COVID-19 infection.

When the researchers took these factors into account, they found that the rates of breakthrough infection were similar between those with SUDs and those without. This means that these factors, not the substances themselves, are what make people with SUDs more at risk of breakthrough infections. Surprisingly, though, cannabis use disorder was still found to be significantly associated with higher rates of infection, even when these factors were controlled for. While researchers do not yet know why that was, they suggest that patients with cannabis use disorder take extra caution to protect their health.

How can I stay safe?

The best way to keep yourself safe from COVID-19 is to get fully vaccinated (both doses). Vaccination is important and necessary to protect yourself from COVID-19. But, if you currently suffer from or have a history of a substance use disorder, you are still at an increased risk of COVID-19 infection even with the vaccine, and you should continue to take protective measures. This includes following public health guidelines, wearing a mask, and physical distancing.

It may also be beneficial to seek treatment for substance use to help strengthen your body, especially your immune system. This way, your body can better fight off COVID-19 infection or more serious cases of infection.

For clinicians, it is recommended to screen patients for SUDs in order to better understand their risks and care needs. For patients with SUDs who contract COVID-19, be alert for a more complicated or serious case and be prepared to support your patient.

Key Takeaways

  • People with substance use disorders have a higher risk of COVID-19 infection, hospitalization, and death, even if they are fully vaccinated. 
  • This risk is highest for those with cannabis or cocaine use disorders. 
  • Vaccination is important to protect yourself from COVID-19, but other health measures are also important to keep yourself safe. This includes wearing a mask, physical distancing, and following public health recommendations.


Wang, L., Wang, Q., Davis, P.B.,  Volkow, N.D. and Xu, R. (2021), Increased risk for COVID-19 breakthrough infection in fully vaccinated patients with substance use disorders in the United States between December 2020 and August 2021. World Psychiatry.

Yasgur, Batya Swift. Substance Abuse Boosts COVID Hospitalization, Death Risk, Even After Vaccination. Medscape Medical News. Published October 14, 2021