Europe has been identified as the region in the world with the lowest level of confidence in vaccine safety¹. However, as HPV vaccination differs from other childhood vaccines, it raises additional concerns. For instance, the fact that the vaccine prevents a sexually transmitted infection has been shown to provoke concerns among parents who believe adolescents are too young to receive such a vaccine, believing that their child is not yet sexually active and feeling that the vaccine could lead to early or unsafe sexual practices.

A systematic literature review conducted by the Vaccine Confidence Project² found that the main reason why European populations are hesitant to accept the HPV vaccine is dissatisfaction with information, claiming that the information provided is unreliable, biased, and/or incomplete (Figure 1). The vaccine is also still perceived to be too new, with insufficient evidence to prove its safety and effectiveness. Fear about potential long-term and severe side effects of the vaccine was found to be the second most common concern among European populations. In most studies, individuals did not specify which side effects they were worried about, but instead described concerns about side effects in general.

When individuals mistrust those communicating about vaccines, perceiving, for instance, that they are not being fully transparent about the potential side effects of the vaccine, it can affect their confidence in the HPV vaccine even if they have received information confirming that the vaccine is safe and effective³. Given that the vaccine is relatively new, they also express concerns that it is still too early to know whether long-term side effects might only be detected in the future.

This link between information, trust, uncertainty and perception of vaccine safety could be further exacerbated in the context of an adolescent vaccine. The period of adolescence is a period of transition, from physiological changes to evolution of personal identity and relationships with friends, as well as changes at school. These changes have been shown to contribute to the development of mental health issues such as anxiety and depression⁴. Anxiety about side effects of HPV vaccination could therefore easily arise during adolescence, but more importantly, anxieties can spread rapidly among adolescents, especially through social media. This was seen with the rapid spread of You-Tube videos of young girls believing to have been affected by HPV vaccination in Denmark, Japan, Colombia, Ireland and the UK.

Figure 1. The graph represents the average proportion of hesitant study participants (that have or would have refused HPV vaccination) across all studies identified in the systematic literature review.

The fact that hesitancy around HPV vaccination might be the product of mistrust and anxiety is also supported by the finding that only a small proportion of study participants believed HPV or cervical cancer is not serious or dangerous enough to warrant vaccination.

Figure 2. Managing HPV vaccine uncertainty. It is crucial to improve efforts on maintaining and re-building public trust in health authorities and vaccine providers as the provision of scientific information alone will not help reduce uncertainty and anxiety around HPV vaccination.

In many countries across Europe, individuals are becoming more sceptical and losing confidence in vaccines, as well as in health authorities, “experts”, and government⁵. This is exacerbated by the increased attention on what is being referred to as post-fact societies, where individuals are increasingly being exposed to alternative and sometimes fake information. It is crucial to improve efforts on maintaining and re-building public trust in health authorities and vaccine providers as the provision of scientific information alone will not help reduce uncertainty and anxiety around HPV vaccination.

References
1. Larson HJ, de Figueiredo A, Xiahong Z, et al. The State of Vaccine Confidence 2016: Global Insights Though A 67-Countries Survey. EBioMedicine 2016;12: 295-301.
2. The Vaccine confidence project. [Available from: http:// www.vaccineconfidence.org/research/vaccine-hesitancy/]
3. Brashers DE. Communication and uncertainty management. Journal of Communication 2001;51(3):477-97.
4. Goodwin NP, Mrug S, Borch C, et al. Peer Selection and Socialization in Adolescent Depression: The Role of School Transitions. Journal of Youth and Adolescence 2012;41(3):320-32.
5. Ravetz J, Saltelli A. Policy: The future of public trust in science. Nature 2015;524(161).