Individual and Geospatial Determinants of Health Associated With School-Based Human Papillomavirus Immunization in Alberta: Population-Based Cohort Study

Abstract

Background: Human papillomavirus (HPV) infection causes nearly all cervical cancer cases and is a cause of anogenital and oropharyngeal cancers. The incidence of HPV-associated cancers is inequitable, with an increased burden on marginalized groups in high-income countries. Understanding how immunization status varies by material and social deprivation, health system, and geospatial factors is valuable for prioritizing and planning HPV immunization interventions.

Objective: The objective of this study was to describe school-based HPV immunization rates by individual and geospatial determinants of health in Alberta, Canada.

Methods: Health administrative data for male and female individuals born in 2004 in Alberta were used to determine HPV immunization status based on age and the number of doses administered in schools during the 2014/2015-2018/2019 school years. Immunization status and its relationship with material and social deprivation and health system factors were assessed by a logistic regression model. Geospatial clustering was assessed using Getis-Ord Gi* hot spot analysis. Mean scores of material and social deprivation and health system factors were compared between hot and cold spots without full HPV immunization using independent samples t tests. A multidisciplinary team comprising researchers and knowledge users formed a co-design team to design the study protocol and review the study results.

Results: The cohort consisted of 45,207 youths. In the adjusted model, the odds of those who did not see their general practitioner (GP) within 3 years before turning 10 years old and not being fully immunized were 1.965 times higher (95% CI 1.855-2.080) than those who did see their GP. The odds of health system users with health conditions and health system nonusers not being fully immunized were 1.092 (95% CI 1.006-1.185) and 1.831 (95% CI 1.678-1.998) times higher, respectively, than health system users without health conditions. The odds of those who lived in areas with the most material and social deprivation not being fully immunized were 1.287 (95% CI 1.200-1.381) and 1.099 (95% CI 1.029-1.174) times higher, respectively, than those who lived in areas with the least deprivation. The odds of those who lived in rural areas not being fully immunized were 1.428 times higher (95% CI 1.359-1.501) than those who lived in urban areas. Significant hot spot clusters of individuals without full HPV immunization exist in rural locations on the northern and eastern regions of Alberta. Hot spots had significantly worse mean material deprivation scores (P=.008) and fewer GP visits (P=.001) than cold spots.

Conclusions: Findings suggest that material and social deprivation, health system access, and rural residency impact HPV immunization. Such factors should be considered by public health professionals in other jurisdictions and will be used by the Alberta co-design team when tailoring programs to increase HPV vaccine uptake in priority populations and regions.

Keywords: co-design; geospatial; human papillomavirus; immunization; population-based; vaccine.

Figure 1

Evolution of Alberta’s human papillomavirus immunization program.

Figure 2

Creation of the study cohort data set. The (n=2751) surplus in the initial cohort when compared to the original Alberta Health Care Insurance Plan (AHCIP) Provincial Registry and linked data sources study cohort was due to the “did not have Alberta coverage at index” exclusion criterion being pre-applied to the AHCIP Provincial Registry but not the Meditech data set. This surplus is removed in the next exclusion step. HPV: Human Papillomavirus.

Figure 3

Conceptual framework of determinants of health that impact student human papillomavirus (HPV) immunization.

Figure 4

Areas of statistically significant clusters of local geographic areas with high (ie, hot spots) and low (ie, cold spots) rates of male and female individuals born in 2004 without full human papillomavirus immunization in Alberta, Canada.