Background In 2010, 76% of Quebec female students aged 14 and 15 received complete HPVV through a publicly funded school-based program where teenagers can elect to be vaccinated (parental consent not mandatory). Quebec's free HPVV program also targeted female teenagers up to age 18 in various settings (mostly public clinics and schools). A study was conducted to identify the determinants of HPVV among Quebec teenagers targeted by the program.

Methods A mailed and electronic survey was conducted in 2010 of a random sample of 3000 females (aged 14 to 18) listed in the public health insurance data registry. The survey questionnaire was based on a model elaborated following an extensive literature review and upon an adaptation of the Health Belief Model and the Walsh and McPhee model. The model developed takes into account the mutual influence of teenagers and their parents, as well as interactions with health professionals, on the vaccination decision. Prior to the survey, two focus groups were conducted with vaccinated and non-vaccinated teenagers to improve the model, and the questionnaire reliability was tested on 110 students aged 14 and 15. The final questionnaire had 38 Likert scale and multiple-choice questions. Bivariate and multivariate analyses were done.

Results The response rate was 46%. Generally, teenagers have a good knowledge of HPVV and the virus transmission. However, 68% thought that men cannot catch the virus. The HPVV coverage for one dose decreases with age: from 94% for teenagers aged 14 to 68% for those aged 17–18 (p<0.001). HPVV was significantly associated with better knowledge, HPVV perceived benefits, vaccination habits, encouragement from the school nurse or a teacher, relatives? Encouragement and parental approval (adjusted OR: 1.1–4.3). Not having HPVV was significantly associated with concern about HPVV side effects, family discouragement, and media promotion of HPVV (adjusted OR: 0.27–0.50).

Conclusions School-based HPVV is more effective in reaching high vaccine uptake. Information on the virus transmission has to be improved; by targeting girls, the program suggests that only females can be infected. Even if their consent is not mandatory for teenager HPVV, parents play a major role in their daughter's vaccination decision. The media influence on unvaccinated teenagers must be deepened as it has a paradoxical impact.