Higher Risk for COVID Breakthrough Infections in People With Substance Use Disorders

Concomitant health disorders appear to contribute to increased risk, NIH research suggests.

An analysis of electronic health records of nearly 580,000 fully vaccinated people in the United States found that the risk of breakthrough SARS-CoV-2 among vaccinated patients with substance use disorders was generally low, but higher than the risk among vaccinated people without substance use disorders. The study, published today in World Psychiatry, is led by researchers from the National Institute on Drug Abuse (NIDA), part of the National Institutes of Health, and Case Western Reserve University in Cleveland, Ohio.

The study also found that co-occurring health problems and adverse socioeconomic health determinants, which are more common in people with substance use disorders, appear to be largely responsible for the increased risk of SARS-CoV-2 breakthrough infections. People with substance use disorders, such as alcohol, cannabis, cocaine, opioids and tobacco use also had an increased risk of serious consequences, including hospitalization and death, after breakthrough infections.

People with cannabis use disorders were 55% more likely to have breakthrough infections than people without substance use disorders, although patients with cannabis use disorders tended to be younger and had fewer co-occurring health problems than those with other cannabis use disorders. substance use.

“First of all, vaccination is very effective for people with substance use disorders, and the overall risk of COVID-19 among vaccinated people with substance use disorders is very low,” said NIDA Director Nora D. Volkow, MD, and one of the study’s lead authors. “We must continue to encourage and facilitate vaccination against COVID-19 in people with substance use disorders, while also recognizing that this group is at increased risk even after vaccination and should continue to take protective measures against COVID-19.”

Analyzes conducted in the early stages of the pandemic found that people with substance use disorders were at increased risk of SARS-CoV-2 infection and more likely to have a serious illness resulting in hospitalization or death. had. This was especially true for black people with substance use disorders. Since then, vaccines have become widely available for people aged 12 and older that significantly reduce the risk of COVID-19 and serious illness.

However, clinical trials evaluating the effectiveness of these vaccines did not specifically include people with substance use disorders. Because many people with substance use disorders are immunocompromised due to drug use and co-occurring diseases, researchers hypothesized that this population could be at increased risk for breakthrough infections after vaccination.

To explore these questions, researchers analyzed electronic health records of nearly 580,000 people in the United States with and without substance use disorders who had been fully vaccinated against COVID-19 between December 1, 2020 and August 14, 2021 and who were not infected with SARS-CoV-2 before vaccination. The status of infection was based on the ICD-10 diagnosis code of COVID-19 or laboratory test confirmed presence of SARS-CoV-2 and related RNA.

They determined the percentage of people in each group who contracted SARS-CoV-2 at least 14 days after their last vaccination. This analysis was repeated after matching patients with and without substance use disorders for demographic characteristics; socio-economic factors that affect health, such as instability of housing or work; and lifelong physical illnesses, such as high blood pressure, heart disease, obesity, or diabetes. The team also examined whether fully vaccinated people with breakthrough infections had a different risk of hospitalization and death than matched people without breakthrough infections.

The researchers found that the risk of breakthrough infections was significantly higher in people with substance use disorders than in those without: 7% of vaccinated people with substance use disorders had a breakthrough infection during the study, compared with 3.6% of those with substance use disorders. the vaccinated people without substance use. diseases. The risk of breakthrough infection varied slightly among people with different substance use disorders, ranging from 6.8% for those with a tobacco use disorder to 7.8% for those with a cannabis use disorder.

The study suggests that the increased risk of breakthrough infections in people with substance use disorders was primarily due to co-occurring diseases and adverse socioeconomic characteristics. When controlling for these factors, people with the most substance use disorders no longer had an increased risk of breakthrough infections. The only exception was people with cannabis use disorders, who were still 55% more likely to have breakthrough infections than people without substance use disorders, although patients with cannabis use disorders tended to be younger and less concomitant. common health problems than those with other substance use disorders. The authors hypothesized that factors such as adverse effects of cannabis on lung and immune function may have contributed to the higher risk of breakthrough infection in this group.

In addition, breakthrough infections have been shown to significantly increase the risk of serious consequences, including hospitalization and death, regardless of the presence of substance use disorders. Of those with substance use disorders, 22.5% of those with breakthrough infection required hospitalization, and 1.7% died during the study period, compared to 1.6% and 0.5%, respectively, among people with disorders in substance use but no breakthrough infection. In addition, the risk of serious outcomes after breakthrough infection was higher in patients with substance use disorders than in patients without substance use disorders.

“We knew from previous studies that people with substance use disorders may be particularly vulnerable to COVID-19 and serious related outcomes. These results highlight that while the vaccine is essential and effective, some of the same risk factors still apply to breakthrough infections,” said Rong Xu, Ph.D., professor in the Center for Artificial Intelligence in Drug Discovery at Case Western Reserve. university. . “It is important to continuously evaluate the effectiveness of COVID-19 vaccines and the long-term effects of COVID-19, especially in people with substance use disorders.”

Reference: “Increased risk of COVID-19 breakthrough infection in fully vaccinated patients with substance use disorders in the United States between December 2020 and August 2021” by L Wang, QQ Wang, PB Davis, et al, October 6, 2021 , World Psychiatry .
DOI: 10.1002/wps.20921