Background and Objective:
The HPV vaccination is considered an essential prevention strategy by the World Health Organization(WHO). The Italian Ministry of Health set the goal to reach the 95% vaccinated female and male population susceptible by age. However, the coverage remains below 70%. Vaccine hesitancy (VH) is linked to the risks and benefits information of HPV immunization, but knowledge alone is insufficient to determine the vaccination choice. Individual decision-making is influenced by cognitive biases that distort severity and costs perception of vaccination behavior. This study aims to provide a characterization of the decision-making and cognitive biases in adolescents and design a promotional strategy targeting HPV VH.

Methods:
The project is bounded into two phases. First, a sample size of 500 subjects aged 14-20 will be investigated through an online questionnaire regarding decision-making and related biases involved in HPV vaccination choice. Secondly, we will implement a promotional intervention in high school population to increase HPV knowledge and vaccine confidence. A before-after study with control will be proposed in different schools: specific web-based dissemination messages framed on HPV vaccination bias, resulted from the previous survey, will be created and distributed through dedicated channels. In the control group, the standard informative intervention will be maintained.

Results:
It is expected an improvement in the understanding of the factors that determine HPV VH and the evaluation of the feasibility and effectiveness of a design-specific promotional campaign through channels suited for adolescents. The results of the campaign will be evaluated according to the vaccination intention of the participants in treatment and control group (Youth Attitudes about Vaccines scale), and through the local administrative data on vaccination rate.

Conclusion:
A de-biasing approach is fundamental to improving health patterns and changing the level of VH. This will result in better vaccine uptake in line with WHO recommendations.