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Why We Shouldn't Get So Depressed About Vaccine Hesitancy

14/09/2016 13:59

The anti-vaccination movement has provoked a degree of despair, particularly in those of us who place great value on the public's engagement with science. It is frustrating to see such vigorous opposition to something that's probably saved more lives than any other medicine, while other more dangerous and less effective medical procedures remain popular.

However, things don't seem so bleak if we distinguish between people who dismiss the importance of vaccination outright, and those who are specifically concerned about their safety. New data, from a vast international study just published by my colleagues and myself, indicate that the global public does indeed understand the importance of vaccination. Far from signalling the twilight of scientific literacy, my own view is that that vaccines' sheer ubiquity may contribute to the doubts about their safety, since even the rarest side-effects are likely to manifest when hundreds of millions of people are immunised each year. I believe stronger and better-publicised regulation might offer some unexpected ways to strengthen public confidence.

Surely vaccines deserve more respect. In the current US presidential campaign, the Republican, Libertarian, and Green Party candidates have all expressed tepid-to-hostile views on vaccines. China is still reeling from the revelation of a criminal ring selling expired vaccines, while distrust and even violence towards health teams in Pakistan is blocking efforts to eradicate polio. The Japanese public has all but stopped using the HPV vaccine following tales of suspected side-effects, which subsequently hopscotched across the globe to Denmark, Ireland, Colombia, and beyond.

It's tempting to see these events as part of an anti-scientific trend - a view adopted in recent pieces by the editorial board of Scientific American and editor-in-chief Jeremy Berg of the journal Science. But these lamentations of a lost "Golden Age" of science tend to conflate the views of the conspiracy fringe (e.g., vaccination is actually a secret genocidal plot) with those of the much larger group of people who are hesitant about specific vaccines, but who don't drag a cumbersome worldview into the matter.

In our sweeping global survey of 65,819 people in 67 countries, 91% agreed with the statement, "Vaccines are important for children to have." On the other hand, only about 83% agreed that, "Overall I think vaccines are safe." Though still a large majority by most standards, this level of confidence in safety is potentially weak enough to undermine herd immunity. In France (the most vaccine-sceptical nation in our survey) we found one of the widest gaps between agreement with vaccines' importance (83%) and agreement that they were safe (50%). The results from each country can be viewed using the interactive tool below.

Interactive country data viewer

Personally, this finding prompted me to take a second look at the common anti-vax soundbite, "I'm not anti-vaccine, I'm pro-safe-vaccines." Though I've been inclined to dismiss high profile anti-vaccine leaders who might only be saying this to appear more moderate while espousing their same old views, our 65,819 respondents have no reason to mince words. To me, this suggests we should focus our efforts on quelling doubts about safety, rather than waste time proselytising vaccination in general.

I would suggest a counterintuitive approach to the safety issue: beefing up the regulation of vaccines. This might seem strange - if vaccines are already safe, why should we spend more time and money regulating them? Because effective regulation, in addition to promoting safety, also promotes the public's confidence. In public health, as in economics, fear leads to hesitation, and uncertainty breeds missed opportunities. The purpose of regulation is not merely to make sure that vaccines are safe, but also to make sure that people believe vaccines are safe, so that they actually get used. I wouldn't expect it to solve all our vaccination woes, but I do find it curious that regulation almost never comes up in conversations about vaccine hesitancy.

Most countries, including the US, evaluate vaccine safety through a variety of tests, the most stringent of these being Phase III clinical trials involving up to ten thousand participants - a large enough group to detect all but the rarest side effects. But when vaccines are rolled out, they are given to so many people that "rare" side effects are almost inevitable. While medical ethics are based on proportions (a 0.0001% chance of harm would be considered very safe), the court of public opinion tends to deal in absolute numbers, since even one death is enough to create a media sensation. More stringent pre-licensure testing could minimise this public opinion problem, and also allow modifying or phasing out the VAERS database, a public record which tracks possible side effects of an approved vaccine, but which is often misinterpreted as a catalogue of confirmed adverse events, stoking unnecessary fear.

Then there is the question of who evaluates the test results. In the US this is the responsibility of the Vaccines and Related Biological Products Advisory Committee, which includes two non-voting representatives of the pharmaceutical industry. In principle this is perfectly appropriate, but it may be worth investing extra effort to find an alternative arrangement. It doesn't matter that the alleged corruption is highly implausible; if people don't believe the system works, then the system isn't completely working.

Certainly we can't afford to intentionally over-regulate every medicine. But vaccines are not like every medicine. They are ubiquitous, entering into the lives of almost everyone in our society, even if only for a moment. This unique aspect of vaccination makes it relevant to the public at large, and so we have a right to expect unusually robust measures to safeguard us. Moreover, it is possible that the anti-vaccine movement has made us too inclined to be tight-lipped; too eager to hold our meetings behind closed doors for fear of hecklers. But we know that people value the importance of vaccines. They just need to be reassured.

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