Vaccine hesitancy and uptake among adolescents: state of the art and implications for public health

Abstract Background Adolescents are currently recommended to receive several vaccines, including, in Italy, those for human papillomavirus (HPV), meningococcal diseases, poliomyelitis, tetanus, diphtheria and pertussis. However, vaccination coverage in this age group is lower than in the pediatric population. Parental decision-making is widely considered a key factor in adolescent vaccination but both parental and adolescent vaccine hesitancy can be responsible of an adverse vaccine behaviors. Few studies have systematically quantified the impact of vaccine hesitancy, defined as the reluctance or refusal to vaccinate despite vaccine availability, on actual vaccine uptake among adolescents, highlighting the need for a comprehensive review of existing evidence. Methods We conducted a systematic search of observational studies involving adolescent populations aged 10 to 19 years, which assessed the relationship between parental and/or adolescent vaccine hesitancy and adolescents’ vaccination status. Databases searched included PubMed, Web of Science, Scopus, and PsycINFO, and the search string was launched on November 19, 2024. We considered all studies that quantitatively evaluated hesitancy, whether using validated tools or not. Data extraction is currently ongoing considering the type of vaccination and the category of adverse vaccine behavior: unvaccinated, untimely vaccinated (based on WHO guidelines), or incompletely vaccinated. Results We expect to find an association between parental and/or adolescent vaccine hesitancy and adverse vaccine behaviors in adolescents. Results will be made available at the time of the conference. Conclusions Final conclusions will be provided upon completion of the systematic review and will be considered to identify interventions to increase vaccination coverage in adolescents.