The "Vaccine Confidence Gap:" How Does Public Mistrust Emerge?

28 Jul 2011
Andrea Titus

We can only wonder about the fallout from the recent revelation of a CIA-organized vaccination campaign in Pakistan, which concurrently collected DNA samples in the hopes of pinpointing the whereabouts of Osama bin Laden.  Pakistan, already a harbor of suspicion towards global vaccination efforts, is also considered to be a ground-zero for polio eradication.

The story brings to light the bigger issue of vaccine mistrust – one of the hurdles facing the loosely formed global vaccine community in the “decade of vaccines.”  NPR’s Shots blog examines this issue more fully, pointing to a recent Lancet study (Larson et al) on vaccines and “public trust” – a multifaceted entity that combines social, psychological, cultural and economic factors into a catalyst for public decisionmaking.

The public mistrust of vaccines leads Richard Horton and Pam Das, in a recent call to action, to the “vaccine paradox” – though vaccines are widely recognized to be one of the most effective, and often cost-effective, public health interventions, ongoing vaccination efforts face obstacles when it comes to both obtaining funding and winning public sentiment.

There are many examples of vaccine wariness.  In India, public hostility emerged after the deaths of four girls were linked to a 2010 HPV vaccine trial (the deaths were later found to be unrelated to the vaccine, though there were ethical concerns associated with the study).  Larson and co-authors highlight another example in northern Nigeria, where local communities boycotted a polio vaccination campaign over fears that the vaccine was a Western scheme to “sterilise Muslims.”

In the U.S., the notion that there is a link between vaccines and autism continues to live on, despite the numerous studies debunking the claim, and the fact that the original article has been recanted and the lead author stripped of his license to practice medicine in the UK.  This case, Larson et al say, is an example of a negative side-effect of the precautionary principle – early concerns about the possible link between thiomersal (a vaccine additive) and autism, and subsequent recommendations to reformulate vaccines to remove the additive, fueled a mistrust that persists today despite scientific evidence pointing wholly in the other direction.

The U.S., however, is still relatively successful in providing routine vaccinations for its children.  Though parents may still have questions, or harbor misperceptions, about vaccine safety, most recommended vaccines reach over 90% of U.S. children.  South Asia is a different story.  Of the 27 million newborns in India each year, less than 44% of them receive the recommended vaccine schedule.

So, there are communication challenges facing vaccine initiatives, particularly as the vaccine arsenal continues to grow in scope and complexity.  Larson and co-authors note that the “list of WHO prequalified vaccines now has 202 products from different manufacturers targeted against 20 infectious agents,” and there are a number of neglected diseases, including dengue, hookworm, and leprosy, which are good candidates for vaccine development as well.  With unprecedented funding and attention focused on the “decade of vaccines,” communicating the benefits of vaccination becomes more critical than ever, even if there will always be detractors.

From the Larson et al article:

Vaccination is a complex social act that effects [sic] 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 account the range of social and political factors that affect the public’s willingness to accept vaccines.

The immunisation community, including scientists, policy makers, and health providers, needs to come to terms with the reality that individuals and groups will continue to question and refuse vaccines. Extremist antivaccination groups whose minds will not change will exist. Many people—the majority—who accept vaccines could change their mind. The focus should be on building and sustaining trust with those who accept and support vaccines, while working to understand and address the growing confidence gap. 

 

Image credit: Flickr: DFID - UK Department for International Development

Health and Development