Equity and impact: Ontario's infant rotavirus immunization program five years following implementation. A population-based cohort study

Vaccine. 2019 Apr 17;37(17):2408-2414. doi: 10.1016/j.vaccine.2019.01.061. Epub 2019 Feb 11.

Abstract

Background: Ontario implemented a publicly-funded rotavirus (RV) immunization program in 2011. Our objectives were to evaluate its impact on hospitalizations and emergency department (ED) visits for acute gastroenteritis (AGE) five years after implementation.

Methods: We performed a population-based longitudinal retrospective cohort study to identify hospitalizations and ED visits for RV-AGE and overall AGE in all age groups using ICD-10 codes between August 1, 2005 and March 31, 2016. A negative binomial regression model that included the effect of time was used to calculate rates, rate ratios (RRs) and 95% confidence intervals (CIs) for AGE before and after the program's implementation, after adjusting for age, seasonality and secular trends. We examined the seasonality of RV-AGE hospitalizations among children under five before and after the program and explored its equity impact.

Results: Following program implementation, RV-AGE hospitalizations and ED visits among children under five years declined by 76% (RR 0.24, 95% CI 0.20-0.28) and 68% (RR 0.32, 95% CI 0.21-0.50), respectively. In addition, hospitalizations and ED visits for overall AGE declined by 38% (RR 0.62, 95% CI 0.59-0.65) and 26% (RR 0.74, 95% CI 0.73-0.76), respectively, among children under age five. Significant reductions in both outcomes were also found across a range of age-strata. In the pre-program period, the mean monthly hospitalization rate for RV-AGE among children residing in the most marginalized neighbourhoods was 33% higher than those residing in the least marginalized (RR 1.33, 95% CI 1.17-1.52), this disparity was not evident in the program period (RR 0.95, 95% CI 0.69-1.32). We found no evidence of a seasonal shift in rotavirus pediatric hospitalizations.

Interpretation: The introduction of routine infant rotavirus immunization has had a substantial population impact in Ontario. Our study confirms herd effects and suggests the program may have reduced previous inequities in the burden of pediatric rotavirus hospitalizations.

Keywords: Equity; Hospitalization; Immunization; Program impact; Rotavirus; Seasonality.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Child
  • Child, Preschool
  • Cohort Studies
  • Female
  • Gastroenteritis / epidemiology*
  • Gastroenteritis / prevention & control*
  • Health Services Accessibility*
  • Hospitalization
  • Humans
  • Immunization Programs*
  • Infant
  • Male
  • Middle Aged
  • Ontario / epidemiology
  • Public Health Surveillance
  • Rotavirus / immunology*
  • Rotavirus Infections / epidemiology*
  • Rotavirus Infections / prevention & control*
  • Vaccination
  • Viral Vaccines / administration & dosage
  • Viral Vaccines / immunology*
  • Young Adult

Substances

  • Viral Vaccines