Factors associated with initiation and completion of the quadrivalent human papillomavirus vaccine series in an ontario cohort of grade 8 girls
1 Department of Community Health and Epidemiology, Queen's University, Carruthers Hall, Kingston, ON, K7L 3N6, Canada
2 Kingston, Frontenac, Lennox, & Addington Public Health, 221 Portsmouth Avenue, Kingston, ON, K7M 1V5, Canada
3 Division of Clinical Epidemiology, McGill University Health Center, 687 Pine Avenue West, Montreal, QC, H3A 1A1, Canada
4 Department of Medicine, McGill University, McIntyre Building, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada
5 Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue, Toronto, ON, M4N 3M5, Canada
6 Department of Family and Community Medicine, University of Toronto, 500 University Avenue, Toronto, ON, M5G 1V7, Canada
7 Dalla Lana School of Public Health, University of Toronto, 155 College Street, Health Science Building, Toronto, ON, M5T 3M7, Canada
8 Public Health Ontario, 480 University Avenue, Suite 300, Toronto, ON, M5G 1V2, Canada
9 Division of Allergy and Immunology, Department of Medicine, Queen's University, Doran 1, Kingston General Hospital, 76 Stuart Street, Kingston, ON, K7L 2V7, Canada
10 Department of Biomedical and Molecular Sciences, Queen's University, Botterell Hall, 20 Stuart Street, Kingston, Ontario, K7L 3N6, Canada
BMC Public Health 2011, 11:645 doi:10.1186/1471-2458-11-645Published: 13 August 2011
Although over a hundred million dollars have been invested in offering free quadrivalent human papillomavirus (HPV) vaccination to young girls in Ontario, there continues to be very little information about its usage. In order to successfully guide future HPV vaccine programming, it is important to monitor HPV vaccine use and determine factors associated with use in this population.
Linking administrative health and immunization databases, we conducted a population-based, retrospective cohort study of girls eligible for Ontario's Grade 8 HPV vaccination program in Kingston, Frontenac, Lennox, and Addington. We determined the proportion of girls who initiated (at least one dose) and completed (all three doses) the vaccination series overall and according to socio-demographics, vaccination history, health services utilization, medical history, and program year. Multivariable logistic regression was used to estimate the strength of association between individual factors and initiation and completion, adjusted for all other factors.
We identified a cohort of 2519 girls, 56.6% of whom received at least one dose of the HPV vaccine. Among vaccinated girls, 85.3% received all three doses. Vaccination history was the strongest predictor of initiation in that girls who received the measles-mumps-rubella, meningococcal C, and hepatitis B vaccines were considerably more likely to also receive the HPV vaccine (odds ratio 4.89; 95% confidence interval 4.04-5.92). Nevertheless, HPV vaccine uptake was more than 20% lower than that of these other vaccines. In addition, while series initiation was not influenced by income, series completion was. In particular, girls of low income were the least likely to receive all three indicated doses of the HPV vaccine (odds ratio 0.45; 95% confidence interval 0.28-0.72).
The current low level of HPV vaccine acceptance in Kingston, Frontenac, Lennox, and Addington will likely have important implications in terms of the health benefits and cost-effectiveness of its publicly funded program. We identified important factors associated with series initiation and completion that should be considered in efforts to improve HPV vaccine use in this population.