Still Low Overall, Breakthrough COVID Rates Elevated for Fully Vaccinated Individuals with SUD

An analysis of electronic health records of nearly 580,000 fully vaccinated individuals found the risk of a breakthrough COVID-19 infection for those with substance use disorders, while still low overall, was greater than the risk for individuals without SUD.

The study was conducted by researchers at the National Institute on Drug Abuse and Case Western Reserve University in Cleveland. Findings were published in the journal World Psychiatry.

Co-occurring health conditions and adverse socioeconomic determinants of health—more common among people with SUD—were determined to be largely responsible for the increased COVID risk. Individuals with alcohol, cannabis, cocaine, opioid and tobacco use disorders were also found to have elevated rates of severe COVID-related outcomes after breakthrough infections.

Researchers looked at records for patients who were vaccinated between Dec. 1, 2020, and Aug. 14, 2021, and who had not been infected with COVID-19 prior to being vaccinated. Of those fully vaccinated, 7% of individuals with SUD had a breakthrough COVID infection during the study, compared to 3.6% of individuals without a substance use disorder. Risk of breakthrough infection varied by substance, topped by 7.8% of those with cannabis use disorder.

Of note: When controlling for factors such as co-occurring diseases and adverse socioeconomic conditions, individuals with most substance use disorders no longer had elevated rates of breakthrough infections. The lone exception was individuals with cannabis use disorder, whose rates remained elevated. Cannabis’ adverse effects on lung and immune system function may have contributed to the increased risk, according to researchers.

“First and foremost, vaccination is highly effective for people with substance use disorders, and the overall risk of COVID-19 among vaccinated people with substance use disorders is very low,” NIDA Director Nora Volkow, MD, one of the lead authors on the study, said in a news release announcing the findings.

“We must continue to encourage and facilitate COVID-19 vaccination among people with substance use disorders, while also acknowledging that even after vaccination, this group is at an increased risk and should continue to take protective measures against COVID-19.”