Understanding hesitancy around vaccines and vaccination: an umbrella review

Abstract

Abstract Background Vaccination has been evaluated and was found to be the most successful and cost-effective interventions to preventing illness and improve health outcomes. However, internationally, an increase in vaccine hesitancy has led to a decrease in vaccination uptake. We conducted an umbrella review to assess the factors related to under-vaccination and non-vaccination from a global perspective. Methods PubMed, EMBASE and Science Direct were searched from inception to December 2019 for systematic reviews and meta-analyses that examined the factors affecting vaccination choices. No restrictions on language, publication date, vaccination type, setting, or population were applied. Narrative and extensive reviews were excluded. A narrative synthesis was undertaken to present the results thematically. Results Twenty-two systematic reviews met the inclusion criteria. The published evidence on this topic shows that, overall, a variety of complex factors exist related to vaccine hesitancy. Across all articles included, the main areas of concern were around vaccine safety and efficacy. Mistrust towards vaccine-related bodies (e.g. pharmaceutical companies, health professionals, researchers etc.), inconvenience, cost, and overall lack of information/knowledge were also identified as major barriers to vaccine uptake. Barriers vary depending on population, place and vaccines. Conclusions Our results show a variety of complex factors influencing the decision to accept, delay or reject some or all vaccines, indicating the necessity of a multi-faceted approach to address them in order to improve vaccine coverage. Key messages The results of this review show that concerns regarding vaccine safety and efficacy were the most significant barriers. Further research, policies, programs, and community-driven initiatives are needed to enhance acceptability and uptake of vaccination.