Vaccine Hesitancy, Refusal and Access Barriers: The Need for Clarity in Terminology

"There is a need to develop and evaluate solutions tailored to the very real challenges of vaccine hesitancy (related to acceptance)..."

The term 'vaccine hesitancy' is used by some experts and commentators to explain all partial or non-immunisation. The authors of this article propose that more precision in the term is needed; only with clear terminology, they argue, can we begin to understand where the problem lies, measure it accurately, and develop appropriate interventions.

In public commentary about vaccination coverage, confusion can arise around: (i) 'Vaccine hesitancy' is represented as a behaviour, even though it is a psychological state; (ii) the label 'hesitancy' is applied to non-vaccination broadly, when some non-vaccinators are forthright in their refusal, and may never have been hesitant; and (iii) 'hesitancy' is used inaccurately as the explanation for under-vaccination in a population when the causes are related to pragmatics, competing priorities, access, or the failure of services or policies.

The authors critically examine the oft-cited World Health Organization (WHO) Strategic Advisory Group of Experts on Immunization (SAGE) definition of vaccine hesitancy, which cites factors such as confidence (do not trust vaccine or provider), complacency (do not perceive a need for a vaccine, do not value vaccination), and convenience (do not have full access to vaccines due to issues around physical availability, geographical accessibility, or the ability to understand because of language or health literacy). The authors contend that adding the concept of 'convenience' to a definition of hesitancy is problematic, and the problem is compounded by the imprecision in the definition of convenience used. They observe that it bundles together concepts relating to individuals' decisions (selecting out or refusing vaccines) with individual and system-level factors that may contribute to difficulties accessing vaccines. In short, the SAGE definition perpetuates terminological imprecision, in their estimation.

The term 'vaccine hesitancy', they assert, should only be applied to those parents whose deliberations demonstrate something akin to indecision. Decisional conflict is an internationally accepted construct with a validated scale where certain scores correlate with action. They suggest under-vaccinated as the overarching term capturing those who are unvaccinated or partially vaccinated for any reason; vaccine uptake is affected by both acceptance and the logistical or opportunity-related factors. Reasons for under-vaccination could then be further expanded into a set of constructs with good content and construct validity. Each needs development of different and tailored interventions to improve uptake.