RSV and all-cause lower respiratory infection burden among infants in remote British Columbia: Retrospective population-based birth cohort study

BackgroundIn 2024, the National Advisory Committee on Immunization recommended universal RSV immunization across Canada, prioritizing infants in remote communities. However, in the absence of population-based data, programs may not effectively narrow health gaps in remote communities. MethodsRetrospective cohort study of all births in British Columbia (BC) from April 2013 to March 2024, followed for 1 year, using health administrative data. Main outcomes were hospitalizations for all-cause and RSV-lower respiratory tract infection (LRTI). Secondary outcomes were tertiary Pediatric Intensive Care Unit (PICU) admissions, length of stay, and air transport. Main exposures were community remoteness and social determinants of health. Incidence rates and incidence rate ratios (IRR) adjusted for sex, prematurity, and chronic conditions were estimated using Poisson generalized estimating equations. ResultsAmong 472,623 infants, those living in remote communities (N=3636) had higher hospitalization risk for all-cause (IRR: 2.91, 95%CI 2.02-3.65) and RSV-LRTIs (IRR: 1.60, 95%CI 1.17-2.19) compared to metropolitan areas. Length of stay and PICU admission rates were similar by region. Almost half (48.8%) of children from remote areas hospitalized for all-cause LRTIs required air evacuation. Infants from remote communities remained at higher risk for all-cause (aIRR 2.84, 95% CI 2.22-3.63) and RSV-LRTI (aIRR 1.56, 95% CI 1.15-2.12) hospitalizations after adjusting for covariates. InterpretationInfants in remote communities experienced a disproportionately high RSV-LRTI burden, supporting prioritized RSV interventions in these regions. The residual risk after accounting for known factors highlights the need to investigate additional drivers of vulnerability in remote areas.