A recent study showed that people with substance use disorders (SUDs) face higher risks for developing COVID and for experiencing serious problems associated with the infection. The study, published in World Psychiatry, examined these risks in fully vaccinated individuals with SUDs.
The study included 579 372 people in the US, of whom 30 183 had a diagnosis of SUD and 549 189 without such a diagnosis) who were fully vaccinated between December 2020 and August 2021 and had not contracted COVID before their vaccinations.
The risk for breakthrough COVID infection in vaccinated people with SUDs ranged from 6.8% for tobacco use disorder to 7.8% for cannabis use disorder, all significantly higher than the 3.6% in the vaccinated non-SUD population. After controlling for demographics (age, gender, ethnicity) and vaccine types (Pfizer, Moderna, Johnson & Johnson), patients with SUDs – with the exception of those with tobacco use disorder – still had higher risks for breakthrough COVID-19 compared with matched individuals without SUDs, with the highest risks for those with cocaine use disorder and cannabis use disorder.
The higher risk for people with SUDs was found to be largely due to their higher prevalence of comorbidities and adverse socioeconomic determinants of health (such as problems related to education, employment, and housing). However, those with cannabis use disorder, who were younger and had less comorbidities, still had a higher risk for breakthrough infection even matching for these. This could indicate that other variables, such as behavioural factors or adverse effects of cannabis on pulmonary and immune function, could explain some of their higher risk for breakthrough infection.
“In our study, the overall risk of COVID infection among vaccinated SUD patients was low, highlighting the effectiveness and the need for full vaccination in this population,” the authors wrote. “However, our findings document that this group remains a vulnerable one even after vaccination, confirming the importance for vaccinated patients with SUD to continue to take protective preventive measures against the infection.”