People with substance use disorders may be at higher risk for COVID breakthrough infections

Getting double jabbed against coronavirus is the best way to protect yourself against the worst effects of the pandemic disease. However, while COVID-19 vaccines boost your immune response against the virus and prevent severe illness and hospitalisation, some people may suffer what is known as a breakthrough infection.

What is a breakthrough infection?

Breakthrough infections occur when people contract COVID despite being fully vaccinated against the virus. But, these breakthrough infections are expected, as while immunisation may reduce the virus’ effects, no vaccine is 100% effective.

Just with any virus, some people are more susceptible than others. According to a new study published in the journal World Psychiatry, those with substance use disorders (SUDs) could have a higher risk of contracting breakthrough coronavirus infections.

Cannabis use disorder linked to 7.8% chance of breakthrough COVID infection

To conduct the study, researchers from the National Institute on Drug Abuse (NIDA) analysed the de-identified electronic health records of almost 580,000 fully vaccinated US residents, including 30,183 with a diagnosis of SUD and 549,189 non-SUD participants, all of which had not contractedCOVID before vaccination.

Key findings indicated that during the study 7% of those with an SUD - depending on either tobacco, alcohol, cannabis, cocaine or opioids - caught a breakthrough infection compared to 3.6% of non-SUD counterparts.

The study found that not only were people with SUDs more prone to breakthrough infection; they were also 22.5% more likely to require hospitalisation. Meanwhile, those who did not depend on any substances had a hospitalisation risk of just 1.6%.

Among those with an SUD, the risk of breakthrough infection ranged from 6.8% (tobacco use) to 7.8% for cannabis use. These high breakthrough rates remained when accounting for demographics and vaccine types for all SUD subtypes.

However, after accounting for comorbidities and adverse socioeconomic conditions in both groups, COVID breakthrough infection risks were no longer significantly different between those with and without an SUD. The exception being those with cannabis use disorders, for who the risk of breakthrough infection remained high.

NIDA Director Dr Nora D. Volkow, one of the study’s lead authors, explained that those with SUDs could be more vulnerable to breakthrough infections, possibly due to weaker immune systems and greater exposure to the virus.

Though vaccines are highly effective against COVID-19, their effectiveness in individuals with SUDs might be curtailed by compromised immune status and a greater likelihood of exposures, added to the waning vaccine immunity and the new SARS-CoV-2 variants

Dr Volkow continued: ‘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.’