There was greater vaccine uptake in the “in-school” vaccination delivery model. Controlling for previous Hepatitis B vaccination status and grade, girls who received HPV vaccination in the “community” delivery model were significantly less likely to be vaccinated if they lived in the most materially deprived neighbourhoods. These results support our hypothesis that those with lower SES were differentially disadvantaged by not having access to an “in-school” vaccination delivery model.
It was expected that there would be a difference in the uptake of HPV vaccine between the two service delivery models simply on the basis of the evidence that school-based delivery programs achieve higher coverage rates than community-based delivery by reducing barriers to access
]. What is not clear, however, is what specific factors contributed to this difference in Calgary. Given that the large dissenting school district is faith-based (Roman Catholic), one possibility might be that the parents actively made the decision to not vaccinate their daughters because of the concerns raised by their religious leaders. This seems unlikely to be the primary factor since we found that girls attending Roman Catholic schools with the in-school delivery were vaccinated at a much higher rate than those attending Roman Catholic schools with the community program, although still slightly less than in the non-denominational schools. Also, in the Roman Catholic school district in Edmonton, another city of similar size in Alberta, permits in-school HPV vaccination, and there was no significant difference in the uptake between the two Edmonton school boards (Alberta Health Services: Human Papillomavirus Vaccination (HPV) Rates 2009–2010
Alberta; 2011). Furthermore, in a provincial survey conducted by Alberta Health and Wellness during the first year of the immunization program, there was no difference found between parents/guardians in Calgary and Edmonton with respect to their intention to consent to the vaccination of their daughters
]. Finally, several parental surveys have included questions about religious affiliation with conflicting results
]. Ogilvie and colleagues found no difference between reported religious affiliations, while Constantine and Jerman found that both Roman Catholics and non-church attendees were more likely to accept HPV vaccination and ‘others’ and born again Christians were less likely
]. Finally, Marlow, Waller, and Wardle found that parents self-identifying with ‘other’ non-Christian religions were less likely to accept the vaccine than respondents who self-characterized as ‘Christian’ or ‘none’
]. There are Catholic students in the Public system and non-Catholic students in the Catholic system in Calgary. We did not have access to the girls’ or their parents’ religious status for either delivery model and therefore were unable to explore this issue further.
The impact of SES has also been somewhat inconsistent in parental surveys. Parents with lower levels of education appear to be more in favour of HPV vaccination than parents of higher education, yet the opposite relationship is seen for parental income; more support for HPV vaccination from parents with higher income compared to parents with low income
]. In Ontario, Smith et al. found that income was not associated with initiation of HPV vaccination; rather it was associated with completion of vaccination
]. The authors speculated that absenteeism was an explanatory factor, since if a child missed days when the vaccinations were given in school they were left with scheduling visits either with family physicians or public health clinics. We believe that this is consistent with our findings, and the interpretation that parents who are economically deprived typically face greater challenges getting their daughters to public health clinics than those parents who are economically better off. The Pampalon material deprivation index contains both economic and educational components so we were not able to identify which components contributed to the differences
Vaccine cost is not a barrier to parents in the Alberta program, since the vaccine is provided by the Government of Alberta, and administration of the vaccine is conducted exclusively by Public Health Nurses in Alberta Health Services. However, vaccine cost has been raised as a concern about the program itself. Ironically, the “community” based delivery model in Calgary has proven to be substantially more expensive than the “in-school” model because of the additional staff time required for follow up calls to parents and for vaccine administration (Alberta Health Services: Costs of Human Papillomavirus Vaccination Services (unpublished observations) Alberta; 2012). This model also introduces costs to the parents related to transportation, time away from work and inconvenience.
Finally, the information gained through this study is useful for identifying subsets of the population within Calgary who are least likely to access and complete publicly-funded HPV vaccinations. The inequity introduced by the lack of access for girls attending some schools in Calgary is compounded by the fact that another important risk factor for cervical cancer, cigarette smoking, is also more prevalent in these same neighbourhoods and that women of lower SES are known to be less likely to receive cervical cancer screening
]. Following the completion of this study, a combination of factors converged resulting in a change in the delivery of vaccinations within the large dissenting public school district from community to “in-school”. The dissemination of these results to school board members, school and parent councils’ concerns about student access to HPV vaccination, and citizen advocates for HPV vaccination all contributed to this change in policy.
We used an area-based material deprivation index as a proxy measure for individual SES as individual data were not available. While, the material deprivation index has face validity for Calgary, the potential for misclassification of SES and thus misclassification bias cannot be eliminated. Linkage of postal code with the SES data was over 99% thus the risk of selection bias is low. Despite these potential limitations the results of this population based study can inform other jurisdictions planning or examining immunization service delivery models.