This program evaluation offers important insights into factors that are associated with parental decisions about receipt of the HPV vaccine in pre-adolescent girls in a program where neither the cost of the vaccine nor access to health care are barriers. In this population-based evaluation of a publicly funded, school-based HPV vaccine program for girls aged 11 y in Canada, parents reported that 65.1% of eligible girls received the first dose of the HPV vaccine, compared to reported receipt of 88.4% for the hepatitis B vaccine, and 86.5% for the meningitis C vaccine. Parents cited vaccine efficacy, advice from a physician, and concerns about daughters' health as the main reasons for choosing to have daughters receive the vaccine. In contrast, concerns about vaccine safety, a desire to wait until their daughter was older, and lack of information were main reasons for not having daughters receive the vaccine. In multivariate modeling, overall attitudes to vaccines and the HPV vaccine, limited concern about the influence of the HPV vaccine on sexual behaviour, and receiving childhood vaccines were associated with having a daughter receive the HPV vaccine. In contrast, family composition (two parents), having more children, and higher education were associated with not having a daughter receive the HPV vaccine. Of note, none of the following factors were associated with decisions to receive the HPV vaccine: religious affiliation, country of birth, or a self-reported history of abnormal Pap smears or cervical cancer.
In a previous study 
, parental intention to have daughters receive the HPV vaccine in British Columbia was 62.8% (95% CI 60.2–65.4), which approximates both the reported parental uptake in this current study at 65.1% and first dose HPV vaccine uptake reported in the provincial clinical immunization record in the province for 2008 of 64.8% 
. This finding indicates that intention to vaccinate studies can be very useful in planning for actual uptake of the HPV vaccine, albeit with limitations. Comparing the intention to vaccinate 
with our study, some common factors emerge as key predictors of intention to vaccinate and actual vaccination. These factors included overall attitudes to vaccines and role of the HPV vaccine on sexual behaviour. In our study of actual HPV vaccine uptake, previous actions around vaccines, including childhood vaccine history, were positively associated with the decision to have daughters receive the HPV vaccine. A higher level of parental education and more traditional family composition, including greater numbers of children and two-parent families, were associated with a decision to not have daughters receive the vaccine. These factors were not evident in the intention to vaccinate survey, underscoring the importance of examining actual rather than intended behaviour.
This evaluation has important implications broadly for HPV vaccine policy, because there were neither financial nor organizational barriers to receipt of the HPV vaccine in this program. The vaccine program was fully funded for all girls in grade 6 and was delivered in schools throughout British Columbia as part of a well-established school-based immunization program. Despite this access to the program, almost 35% of parents elected not to have their daughters receive the HPV vaccine. In an examination of parents of almost 3,000 girls aged 12 and 13 y in Manchester, United Kingdom, vaccine uptake was 70.6% for the first dose 
, and parents identified vaccine safety and long term data as a key factor in vaccine refusal. In a qualitative study of 52 parents, Dempsey et al. found that parents identified lack of knowledge, safety, and a perception that their daughter was too young as factors associated with declining of the HPV vaccine 
. In a study of 153 mothers that included both those intending to have daughters vaccinated and those who had vaccinated their daughters, less education, parental history of a sexually transmitted infection, parental supervision, and acceptance of the vaccine schedule were associated with HPV vaccine acceptance 
. The findings of these studies echo those found in this study in which parents expressed concerns about the long term safety of the HPV vaccine as a primary reason for refusing to have daughters vaccinated. Parents who did not permit their daughters to receive the vaccine were also concerned about the young age of their daughters, believed the vaccine condoned sexual activity, or believed their daughter was at low risk for acquiring HPV. It is noteworthy that in British Columbia, prior to implementation of the HPV vaccine program, one of the most comprehensive vaccine education programs to date for the province was implemented. These efforts targeted issues such as vaccine safety and efficacy and were delivered in several user-friendly formats including the www.immunizeBC.ca
Web site, through DVDs targeted at parents and girls, as well as with pamphlets and brochures and locally held information sessions for parents and providers. In addition, this vaccine was strongly recommended by several independent expert health groups, such as the Canadian National Advisory Committee on Immunizations 
. However, despite these efforts, many parents still perceived that information was inadequate for them to make an informed decision about HPV vaccination.
In keeping with the findings of two recent studies, this evaluation noted that parents with more education were less likely to consent to their daughters receiving the HPV vaccine 
. This is a surprising outcome, and in contrast to most studies on vaccine rates in children and maternal education, where higher maternal education is associated with higher childhood vaccine rates 
. There are several differences to consider as we compare our findings to existing literature. The HPV vaccine program in British Columbia is delivered in optimal conditions with limited barriers, and so several of the issues that may cause lower uptake rates in less-educated parents in other jurisdictions may not be operating for this program. Specifically, the HPV vaccine program in British Columbia is part of a well-established adolescent school-based vaccine program, where vaccines are offered at school, during school hours, by trained health professionals. As a result, parents do not need to get prescriptions, leave work, or arrange to bring children to an office or clinic to receive the vaccine. Parents do not need to pay for the vaccine, so there are no financial constraints for parents. Nurses return to schools several times so that children have the opportunities on other occasions to receive their vaccinations. Our evaluation examined uptake of vaccines in an adolescent as opposed to infant/toddler population, so some of the previous findings and underpinning barriers for infants/toddlers may not be as relevant. This evaluation also examined a newly launched as opposed to a well-established vaccine, and so the factors operating in parental decision making may also be different.
Literature has noted that, in settings with low childhood vaccine uptake rates in less-educated mothers, programmatic structures can reduce the impact of maternal education on vaccine uptake rates. In a recent review by Racine 
, higher maternal education, independent of income and race/ethnicity, was associated with higher child immunization rates. He found, however, that in jurisdictions where there were greater subsidies for childhood vaccines, there was a significantly smaller difference between rates of immunization in children of less versus more educated mothers. This analysis of US data proposed that with increased public funding for vaccines, many of the barriers that create the immunization rate gradient, such as price and availability, decline in their importance, and the advantages offered by maternal education with respect to childhood vaccine receipt are attenuated. In a setting such as British Columbia, where there are even more programmatic advantages such as offering the vaccine in the school setting, the factors that lead to lower uptake rates in less-educated parents in other settings may be diminished by the organization of the adolescent immunization program in the province.
Further research and examination is needed to understand this unique relationship. In a recent qualitative study on Texan parents who opt out of childhood vaccine programs, Gullion et al. noted that the parents were highly educated and reported very sophisticated data collection and information processing from a variety of sources including online sources 
. Educated parents are often more likely to have access to the Internet and other forms of media compared with less-educated parents in the province, and may feel more comfortable researching the Internet for vaccine information. This research may increase access to some of the Web sites that provide contradictory and potentially inaccurate information about the HPV vaccine and increase parents' concerns about vaccine risks. Highly educated parents may also perceive that they are able to interpret complex scientific and clinical health information and trials independently without the assistance of practitioners. In Gullion's work, parents reported high distrust of the medical community and felt that they were better equipped to conduct research on vaccines and more knowledgeable than the medical practitioners on the topic of vaccines 
. Educated parents may also have felt more comfortable delaying their daughters' vaccination beyond aged 12 y as they would be able to purchase the vaccine privately in the future, should they choose to do so. Guillon's study noted that parents often felt rushed regarding decisions around vaccines, and so the perceived opportunities for discussion about the attributes and risks of vaccines were limited. Clearly, there is a need for further exploration of this topic to understand why educated parents chose to decline the HPV vaccine for their daughters. As educated parents can often be opinion leaders within their communities and school groups, it is particularly important to consider ways to ensure that these parents have accurate information about this and other vaccines, and appropriately contextualize vaccine risk and safety with the risks and sequelae of the vaccine-preventable disease.
Parents who were concerned about the potential impact of the HPV vaccine on sexual practices were less likely to have their daughters receive the HPV vaccine. Over the past 10 y, British Columbia has had a hepatitis B vaccine program for 11-y-old girls and boys. In the corresponding time period, the Canadian provincial adolescent health survey has reported an improvement in sexual practices in adolescents, with delayed sexual debut, as well as safer sexual practices, despite the availability of a vaccine for a sexually transmitted infection in a publicly funded school program in the province 
. It will be critical to ensure that parents are aware that provincial data have shown that the use of a vaccine for a sexually transmitted infection does not increase risky sexual behaviour.
The goal of this evaluation was to inform, in real time, vaccine promotion efforts in the province of British Columbia to ensure that educational efforts responded to the concerns of the population. From this survey, it is clear that messaging should continue to focus on the effectiveness of the HPV vaccine, and continue to highlight the established safety of the HPV vaccine, as well as the importance and safety of vaccines in general. Health professionals remain central in influencing parents' decision around the HPV vaccine, and education should also target physicians and nurses to ensure that they also possess accurate information for parents who seek their council. Parents need to be aware that the use of a vaccine for a sexually transmitted infection (hepatitis B) over the past 10 y in British Columbia has not adversely affected the sexual health of adolescents 
. In contrast, during this same time period, they appear to be making better sexual health decisions.
Limitations of this study include our inability to access parents in two health service areas that account for ~15% of the population of the province and the use of a telephone methodology. Although there were quality assurance interviews both at training with a random review of telephone calls by supervisors and individual quality assurance reviews for data entry, participants were not surveyed twice. Telephone surveys are biased towards English speakers, and there were 304 potential households who could not participate in this evaluation because of a language barrier. However, this was not a random digit survey, and we were able to use telephone numbers provided to public health services by parents, so biases towards access to land lines should be greatly diminished. Regardless, the reported HPV vaccine uptake rate in this evaluation mirrored the uptake rate reported through the provincial clinical immunization record in the province of 64.8% 
. With a population-based, randomly selected sample of over 2,000, representing almost 10% of the eligible population for the program, we expect these findings to be highly generalizable and informative for HPV vaccine policies in high-income countries worldwide.
This study is one of the first population-based assessments of factors associated with HPV vaccine uptake in a publicly funded school-based program worldwide. Policy makers need to consider that even with the removal of financial and health care barriers, parents, who are key decision makers in the uptake of this vaccine, still possess some hesitancy to have their daughters receive the HPV vaccine. As populations become less familiar with the diseases that vaccines prevent and the sequelae of these diseases, there is a greater focus on the adverse events associated with vaccines, without the consideration of the morbidity and mortality associated with the disease itself, nor the burden of disease averted by the vaccine 
. The experience with the HPV vaccine highlights the continued need to ensure that the public is informed and receives credible and clear information about both the scientific evidence for immunizations, as well as information about adverse events associated with vaccines in context. Use of the news media, including the Internet, is essential for connecting with the population, and policy makers must ensure that information speaks broadly to the overall benefits of vaccines at a population and individual level, as well as highlighting the attributes of particular vaccines.