A systematic review of factors that influence the acceptability of vaccines among Canadians.

BACKGROUND: Canada's National Advisory Committee on Immunization (NACI) provides guidance on the use of vaccines in Canada. To support the expansion of its mandate to include considerations for vaccine acceptability when making recommendations, the NACI Secretariat developed a matrix of factors that influence acceptability. To inform and validate the matrix, we systematically reviewed evidence for factors that influence vaccine acceptability, and for interventions aimed at improving acceptability. METHODS: On 10-11 October 2018 we searched four bibliographic databases, the Theses Canada Portal, and ClinicalTrials.gov. Two reviewers agreed on the included studies. From each study, we extracted information about the participants, intervention or exposure, comparator, and relevant outcomes. Due to heterogeneity in the reported factors and acceptability indicators we synthesized the findings narratively. We appraised the certainty of evidence using GRADE. For each vaccine-preventable disease we populated a matrix of factors for which there was evidence of an influence on acceptability. RESULTS: One hundred studies (>1 million participants) contributed data relevant to the public, 16 (6191 participants) to healthcare providers, and three (84 participants) to policymakers. There were 43 intervention studies (~2 million participants). Across vaccines, we identified low certainty evidence for 70 factors relevant to the general population, 56 to high-risk groups, and 30 to healthcare providers. The perceived safety and importance of the vaccine, vaccination history, and receiving a recommendation from a healthcare provider were common influential factors. We found low certainty evidence that reminders for childhood vaccines and policies or delivery models for rotavirus vaccines could improve uptake and coverage. Evidence for other interventions was of very low certainty. CONCLUSIONS: The NACI vaccine acceptability matrix is useful for categorizing acceptability factors for the general public. Reminder systems may improve the uptake of childhood vaccines. Policies that make the rotavirus vaccine universally available and easily accessible may improve coverage. FUNDING: This systematic review was completed under contract to the Public Health Agency of Canada, Contract #4600001536.

A framework for the systematic consideration of ethics, equity, feasibility, and acceptability in vaccine program recommendations.

For the successful implementation of population-level recommendations, it is critical to consider the full spectrum of public health science, including clinical and programmatic factors. Current frameworks may identify various factors that should be examined when making evidence-informed vaccine-related recommendations. However, while most immunization guidelines systematically assess clinical factors, such as efficacy and safety of vaccines, there is no published framework outlining how to systematically assess programmatic factors, such as the ethics, equity, feasibility, and acceptability of recommendations. We have addressed this gap with the development of the EEFA (Ethics, Equity Feasibility, Acceptability) Framework, supported by evidence-informed tools, including Ethics Integrated Filters, Equity Matrix, Feasibility Matrix, and an Acceptability Matrix. The Framework and tools are based on five years of environmental scans, systematic reviews and surveys, and refined by expert and stakeholder consultations and feedback. For each programmatic factor, the EEFA Framework summarizes the minimum threshold for consideration and when further in-depth analysis may be required, which aspects of the factor should be considered, how to assess the factor using the supporting evidence-informed tools, and who should be consulted to complete the assessment. Research, particularly in the fields of vaccine acceptability and equity, has validated the utility and comprehensiveness of the tools. The Framework has been successfully used in Canada for clear, timely, transparent vaccine guidance with positive stakeholder feedback on its comprehensiveness, relevance and appropriateness. Applying the EEFA Framework allows for the systematic consideration of the spectrum of public health science without a delay in recommendations, complementing existing decision-making frameworks. This Framework will therefore be useful for advisory groups worldwide to integrate critical factors that could impact the successful and timely implementation of comprehensive, transparent recommendations, and will further the global objective of developing practical and evidence-informed immunization policies.