ASMA KHALID, HOST:
Throughout this pandemic, we've seen how some Americans have disproportionately suffered from COVID-19. The impacts are worse for racial and ethnic minorities and for people with low-income or high-risk jobs. But there's another group, little discussed, that is also heavily affected. NPR's Will Stone explains.
WILL STONE, BYLINE: People with substance use disorders get infected with the coronavirus more often. Not only that - they're more likely to end up in the hospital and die from COVID-19 than people without an addiction. This is what researchers like Dr. Nora Volkow found in the early days of the pandemic. Volkow directs the National Institute on Drug Abuse. She says what they did not know is, would this still be true once people were vaccinated?
NORA VOLKOW: What we found was that, indeed, individuals with a substance use disorder are at a significantly higher risk of getting a COVID infection after they had been fully vaccinated.
STONE: In fact, those patients are twice as likely to experience a breakthrough infection compared to those without addictions. And it wasn't just that.
VOLKOW: So they were much more likely to end up hospitalized, and they were also much more likely to die.
STONE: Volkow says their latest study finds the heightened risk of breakthrough infections cuts across a whole range of substances - tobacco, alcohol, cocaine, opioids and cannabis. They suspect there are two major reasons. First, people with substance use disorders also have much higher rates of chronic health problems, including hypertension, diabetes and heart disease.
VOLKOW: Which are conditions that, in turn, have been associated with worse outcomes for COVID and greater vulnerability.
STONE: The other is that people with an addiction are more likely to have what researchers call adverse socioeconomic determinants of health - in other words, things like not having a job or stable housing.
CALEB BANTA-GREEN: Really big things that would influence any of our health, including people who also have addiction.
STONE: Caleb Banta-Green researches public health at the University of Washington. Green wasn't involved in this study, but he says it's powerful because the researchers were able to analyze the data and show that substance use did not, in and of itself, explain the findings.
BANTA-GREEN: But yes, they have higher rates of breakthrough infections. But once they accounted for other health care issues and their socioeconomic status, those differences almost entirely disappeared.
STONE: The only exception was for people who use cannabis. For that group, even after controlling for socioeconomic factors and health problems, the risk of a breakthrough infection was still elevated. The study was based on more than half a million electronic health records. And Dr. Josh Barocas at the University of Colorado says working with this data has its limits, so it's hard to draw big conclusions about any particular drug of abuse.
JOSH BAROCAS: Really, the lesson here, instead of pinpointing which substance may or may not be less risky, is more, how do we support this population who are clearly at risk?
STONE: The CDC does count substance use disorder as one of the medical conditions more likely to have severe illness from COVID-19. But Barocas says this doesn't get the same attention as other risk factors.
BAROCAS: Because it's stigmatized and because the solutions aren't as straightforward as I think we would like.
STONE: And yet more than 20 million Americans are believed to have a substance use disorder. Many more are in recovery. And Barocas says the latest research makes it clear the solution needs to be more than just giving someone a vaccine. Will Stone, NPR News. Transcript provided by NPR, Copyright NPR.