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