Elsevier

The Lancet

Volume 378, Issue 9790, 6–12 August 2011, Pages 526-535
The Lancet

Series
Addressing the vaccine confidence gap

https://doi.org/10.1016/S0140-6736(11)60678-8Get rights and content

Summary

Vaccines—often lauded as one of the greatest public health interventions—are losing public confidence. Some vaccine experts have referred to this decline in confidence as a crisis. We discuss some of the characteristics of the changing global environment that are contributing to increased public questioning of vaccines, and outline some of the specific determinants of public trust. Public decision making related to vaccine acceptance is neither driven by scientific nor economic evidence alone, but is also driven by a mix of psychological, sociocultural, and political factors, all of which need to be understood and taken into account by policy and other decision makers. Public trust in vaccines is highly variable and building trust depends on understanding perceptions of vaccines and vaccine risks, historical experiences, religious or political affiliations, and socioeconomic status. Although provision of accurate, scientifically based evidence on the risk–benefit ratios of vaccines is crucial, it is not enough to redress the gap between current levels of public confidence in vaccines and levels of trust needed to ensure adequate and sustained vaccine coverage. We call for more research not just on individual determinants of public trust, but on what mix of factors are most likely to sustain public trust. The vaccine community demands rigorous evidence on vaccine efficacy and safety and technical and operational feasibility when introducing a new vaccine, but has been negligent in demanding equally rigorous research to understand the psychological, social, and political factors that affect public trust in vaccines.

Introduction

Tremendous progress has been made in the development of new vaccines, along with increasing access to new and underused vaccines in the lowest income countries. But, vaccines—often lauded as one of the greatest public health interventions—are losing public confidence. Some vaccine experts describe the problem as a “crisis of public confidence”1 and a “vaccination backlash”.2

Public concerns about vaccine safety and vaccine legislation are as old as vaccines themselves—dating back to the anticompulsory vaccination league against mandated smallpox vaccination in the mid-1800s.3, 4 Some common concerns shared by the antivaccination groups of the 1800s and those of today are related primarily to arguments against mandated vaccination, or imposed vaccine schedules. But current antivaccination groups have new levels of global reach and influence, empowered by the internet5 and social networking capacities allowing like minds to rapidly self-organise transnationally, whether for or against vaccines.6 These groups reach people who are not necessarily against vaccines, but who are seeking answers to questions about vaccine safety, vaccine schedules, changing policies, and the relevance of some new, and old, vaccines. Vaccines evoke concerns different from other health interventions because many healthy people need to be vaccinated to achieve a protective public health benefit.

Several factors drive public questions and concerns: perceptions of business and financial motives of the vaccine industry and their perceived pressures on public institutions—such as during the H1N1 influenza response; coincidental rather than causal adverse events that are perceived as vaccine related; challenges in management and communication of uncertainty about risks7 (including serious, albeit rare, ones); less risk tolerance for vaccines given to those who are healthy than for drugs given to treat an illness; scepticism of scientific truths, which later become untruths, or amended truths as new research becomes available;8 elitism of a group of people that believe they should not risk vaccination of their child if enough other children are being vaccinated; and, in some cases, outright non-acceptance of scientific evidence such as in the case of antivaccine movements that persist in the belief that autism can be caused by thiomersal or the measles, mumps, and rubella (MMR) vaccine, despite an abundance of scientific evidence that shows no causal effect.9, 10

Key messages

  • Public concerns about vaccines are not merely about vaccine safety, but are also about vaccine policies and recommendations, vaccine costs, and new research findings.

  • Public decision making related to vaccine acceptance is complex and is neither driven by scientific nor economic evidence alone, but is also driven by a mix of scientific, psychological, sociocultural, and political reasons, all of which need to be better understood.

  • The internet and new forms of social media have not only allowed for rapid and ubiquitous sharing of information—and misinformation—but have also allowed new methods of self-organisation and empowerment of newly founded online communities that argue against or for vaccines.

  • Although communication of positive, evidence-based information about the safety of specific vaccines and their benefit–risk ratios to the public is crucial, communication alone will not stop public distrust and dissent against vaccines.

  • Levels of public trust in vaccines are highly variable and context specific. To sustain or restore confidence in vaccines, a thorough understanding is needed of the population's—or subpopulation's—specific vaccine concerns, historical experiences, religious or political affiliation, and socioeconomic status.

  • Core principles to be followed by all health providers, experts, health authorities, policy makers, and politicians include: engagement with and listening to stakeholders, being transparent about decision making, and being honest and open about uncertainty and risks.

Although communication of candid, evidence-based information to the public about the safety of specific vaccines and their benefit–risk ratios is crucial, this information alone will not stop public distrust and dissent against vaccines. Public decision making related to vaccine acceptance is not driven by scientific or economic evidence alone, but is also driven by a mix of scientific, economic, psychological, sociocultural, and political factors, all of which need to be understood and taken into account by policy and other decision makers.

We discuss factors in the changing global environment that have precipitated what some in the specialty of climate change call “an erosion of trust”,11 caused by a small minority of climate change sceptics. The vaccine community faces similar challenges. We examine key determinants of trust, with specific examples in which public distrust undermined vaccine acceptance and interrupted immunisation programmes, and, then, what was done to restore trust. Finally, we outline ways to improve public trust including future research and actions that can be taken now.

Section snippets

Background

Many proposed explanations exist as to why vaccines are questioned by the public, what exactly is being questioned, and what can be done to restore public confidence. One common perception is that waning public trust in vaccines is because vaccines have become a victim of their own success—whereby they have been so effective for prevention of disease that more attention has now been focused on the potential risks of vaccines than on the risks of the now less prevalent diseases they prevent. In

Determinants of public trust in vaccines

Public trust in vaccines is a complex issue that often has many converging determinants. Research into environmental-risk communication has identified three factors that affect the extent to which an individual or institution is trusted: perceptions of knowledge and expertise, openness and honesty, and concern and care.32 The credibility of vaccine information, for example, is influenced by the perceived trustworthiness of the messenger—whether a government authority, the vaccine industry, a

The way forward: who needs to do what?

The foregoing examples show that the process of building, rebuilding, and sustaining public trust in vaccines is highly variable and depends on a thorough understanding of the community and its socioeconomic status, previous experience, views of those they trust (and distrust) including religious or political leaders, and understanding of the risks and benefits of vaccines versus the diseases they prevent.

Traditional principles and practices of vaccine communication remain valid,63 especially

Conclusion

Vaccination is a complex social act that effects both direct, perceived self-interest, the interest of one's children, and the broader community. The decision leading to immunisation remains a personal summation of each individual's perception of the complexity of information they receive and their trust in the institutions that produce, legislate, and deliver vaccines. For vaccines to realise their full potential in protection of health, public and private health practices need to take into

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