Abstract
OBJECTIVES: This study aims to identify COVID-19 breakthrough infections among people with HIV (PWH) across different phases of the pandemic and explore whether differential immune dysfunctions are associated with breakthrough infections. DESIGN AND METHODS: This retrospective population-based cohort study used data from an integrated electronic health record (EHR) database in South Carolina (SC). Breakthrough infection was defined as the first COVID-19 diagnosis documented in the state agency after the date an individual was fully vaccinated (ie, 2 doses of Pfizer/BNT162b2 or Moderna/mRNA-1273, or 1 dose of Janssen/Ad26.COV2.S) through June 14, 2022. We analyzed the risk and associated factors of the outcome using Cox proportional hazards models. RESULTS: Among 7596 fully vaccinated PWH, the overall rate of breakthrough infections was 118.95 cases per 1000 person-years. When compared with the alpha-dominant period, the breakthrough infection rate was higher during both delta-dominant (HR: 1.50; 95% CI: 1.25 to 1.81) and omicron-dominant (HR: 2.86; 95% CI: 1.73 to 4.73) periods. Individuals who received a booster dose had a lower likelihood of breakthrough infections (HR: 0.19; 95% CI: 0.15 to 0.24). There was no association of breakthrough infections with degree of HIV viral suppression, but a higher CD4 count was significantly associated with fewer breakthroughs among PWH (>500 vs <200 cells/mm3: HR: 0.68; 95% CI: 0.49 to 0.94). CONCLUSIONS: In our PWH population, the incidence of breakthrough infections was high (during both delta-dominant and omicron-dominant periods) and mainly associated with the absence of a booster dose in patients older than 50 years, with comorbidities and low CD4 count.