Incidence of Herpes Zoster Infection (Shingles) Among Adults Living With and Without HIV in British Columbia, Canada: A Population-Based Study.

Abstract

Herpes zoster (HZ) incidence is elevated among immunocompromised populations, including people living with HIV (PLWH). We evaluated HZ incidence, associated risk factors, recurrence, and post-vaccination HZ occurrence among PLWH compared with people living without HIV (PLWoH) in British Columbia, Canada. We conducted a retrospective, population-based matched cohort study using data from the Comparative Outcomes and Service Utilization Trends (COAST) study (2000-2019). PLWH aged ≥19 years initiating antiretroviral therapy were propensity-score matched to PLWoH from the general population. Incident HZ was identified from administrative health records using a 12-month washout. Age-stratified time-to-event, competing-risk, and multivariable models were used to estimate incidence, risk factors, recurrence, and vaccination-associated outcomes. Among 9,053 PLWH and 9,053 matched PLWoH, HZ incidence rates were higher among PLWH overall. Before vaccine availability, PLWH experienced substantially higher HZ hazards than PLWoH, particularly among participants aged <50 years. After 2009, HZ risk remained elevated among younger PLWH, while hazards were similar between groups among those aged ≥50 years. HZ recurrence was approximately twice as frequent among PLWH. Among PLWH, advanced immunosuppression, including low CD4 cell counts and unsuppressed viral load, and selected comorbidities were independently associated with higher HZ risk. Post-vaccination HZ incidence was low in both populations, with no meaningful difference between PLWH and PLWoH; breakthrough events were uncommon. PLWH remain at increased risk of HZ and recurrence, especially if younger or immunosuppressed. Vaccination was associated with a lower HZ risk supporting expanded access to recombinant zoster vaccination for immunocompromised adults irrespective of age.