COVID-19 Breakthrough Infection after Vaccination and Substance Use Disorders: A Longitudinal Cohort of People with and without HIV Receiving Care in the United States Veterans Health Administration.

Research regarding HIV, substance use disorders (SUD), and SARS-CoV-2 infections after COVID-19 vaccination is limited. In the Veterans Aging Cohort Study (VACS)-HIV cohort, we followed vaccinated persons with HIV (PWH) and without HIV (PWoH) from 12/2020 to 3/2022 and linked SARS-CoV-2 test results for laboratory-confirmed breakthrough infection through 9/2022. We examined associations of substance use (alcohol use disorder [AUD], other SUD, smoking status) and HIV status and severity with breakthrough infections, using Cox proportional hazards regression hazard ratios (HR). To test for potential interactions between substance use and HIV, we fit survival models with a multiplicative interaction term. Among 24,253 PWH and 53,661 PWoH, 8.0% of PWH and 7.1% of PWoH experienced COVID-19 breakthrough. AUD (HR 1.42, 95% CI 1.32, 1.52) and other SUD (HR 1.49, 95% CI 1.39, 1.59) were associated with increased risk of breakthrough, and this was similar by HIV status (p-interaction > 0.09). Smoking was not associated with breakthrough. Compared to PWoH, PWH at all HIV severity levels had increased risk of breakthrough ranging from 9% for PWH with CD4 count ≥ 500 cells/µl (HR 1.09, 95% CI 1.02, 1.17) to 59% for PWH with CD4 count < 200 (HR 1.59, 95% CI 1.31, 1.92). Patients with AUD (HR 1.42, 95% CI 1.33, 1.52) and other SUD (HR 1.48, 95% CI 1.38, 1.59) had increased COVID-19 breakthrough risk, regardless of HIV status. HIV was associated with breakthrough; risk was greatest among PWH with lower CD4 count. In addition to inhibiting HIV treatment adherence and increasing HIV progression, AUD and other SUD may increase COVID-19 breakthrough risk.