HPV vaccine hesitancy: systematic review on determinants and sources of knowledge through the analysis of gender neutral scientific literature

Introduction: The purpose of the study is to analyse sources of knowledge on HPV vaccine, their impact on determinants of hesitancy, defined as the delay in acceptance or refusal of vaccination despite availability of vaccination services, and to evaluate the effectiveness of gender-neutral interventions in addressing hesitancy in parents, adolescents and young adults. The relevance of this work lies in the public health challenge to eliminate an extremely common virus, responsible for over 90% of cervical cancer cases in women, but also for many other cancer types affecting all genders. Methods: The research question posed was: “Does gender-neutral vaccination messaging increase uptake and willingness as compared to gender-focused messaging?”. The research string was run on three databases (PubMed, Trip and the Cochrane Library). Papers were screened by title and then by abstract to obtain a final sample of 106 papers. Data extracted for the population of interest concerned study design, area of study, period of study, education level and socio-economic status of the study population, determinants of hesitancy, type of intervention, gender target of intervention (gender focused vs neutral), vaccination uptake, willingness, knowledge and sources of knowledge. Papers were included if the sample was composed by adolescents, parents or young adults; if they evaluated HPV-vaccine uptake and willingness; if they presented gender-neutral or gender-focused interventions to promote HPV vaccination. They were excluded if they reported non-vaccine-related outcomes; if they were not primary literature; if they did not provide the data of interest for extraction. Results: 71% of the studies were held on developed countries, highlighting inequalities and the need to perform more research in developing countries. Overall, health care practitioners proved to be a determining source of information, cited by the majority of studies. The major determinants of hesitancy were misinformation and lack of information, followed by safety concerns. Of the 106 studies, 31 presented interventions, of which 64% were gender neutral, 23% female-focused and 13% male-focused. Gender-focused interventions proved necessary for normalising vaccine uptake among the whole target population of all genders; gender-focused interventions also still prove relevant in addressing gender-specific challenges. Conclusions: The results suggest the need to implement both gender-neutral and gender-focused campaigns according to need. Since lack of information stands out, associated with safety concerns, as the main determinant of hesitancy, and health care practitioners are identified as the main source of knowledge in the matter, it is necessary to implement research on comprehensive strategies that help gain trust and build dialogue to increase acceptance.