Coverage from Ontario, Canada's school-based HPV vaccine program: the first three years.

Background: In 2007, Ontario implemented a school-based human papillomavirus (HPV) vaccination program targeting grade 8 girls. Girls may complete the series in grade 9 (extended eligibility). Limitations in the existing provincial data sources for assessing HPV vaccine coverage in Ontario prompted the use of two surveys of Health Units (HUs) to calculate provincial vaccine coverage for the first three years of the vaccination program.

Methods: We surveyed Ontario's 36 HUs in March and November 2011 to obtain vaccine coverage information, including source of denominator data, and use of local information systems. The second survey was necessary in order to assess coverage including extended eligibility for the third year. HU-reported HPV vaccine coverage was compared to coverage estimates obtained from two provincial systems: the Immunization Records Information System (IRIS) and the HPV reimbursement database, a system used to remunerate HUs for HPV vaccine doses administered.

Results: 100% of HUs participated in the two surveys. The provincial coverage estimates using HU-reported data were: 51% (2007-2008), 58% (2008-2009), and 59% (2009-2010) with large variation by HU. Coverage increased significantly over time. The number of HUs that were able to report on doses given as part of extended eligibility also increased over time (47% in 2007-2008 to 89% in 2009-2010; p=0.0008). Comparisons across the three data sources (survey, IRIS and reimbursement database) revealed significantly different coverage estimates. Class or school lists were the most common source of denominator data used by HUs (27/36, 75%), however independent schools were not included by all.

Conclusions: As not all HUs were able to report on HPV vaccine coverage including extended eligibility doses these findings likely underestimate the true coverage attained by Ontario's program. Although coverage is below the Canadian Immunization Committee benchmark of 80% within two years of program implementation, the upward trend in coverage is encouraging.