The truth about vaccines Why is one of the most effective medical interventions known to humanity regarded with such mistrust?

Last week was a big week for vaccines. As well as the government’s flu vaccine push, initial results from two new COVID-19 vaccine trials appeared in the journal The Lancet — one from the UK and one from China. They join a US trial from the week before in showing that their candidate vaccines have tolerable side-effects and definitely do cause an immune response. These Phase I and Phase II trials are just the first — albeit crucial — steps on the way to finding a working vaccine. Next, we move to larger, Phase III trials that involve many thousands of people, testing whether those who get the vaccine are actually less likely to catch Covid-19 than those who are injected with a placebo.

It does feel somewhat ironic that The Lancet in particular is taking the lead in publicising the research on Covid-19 vaccines: besides being a super-prestigious medical journal, the main public claim to fame of that particular journal is in publishing one of the worst and most damaging vaccine studies of all time. That was, of course, Andrew Wakefield’s notorious Lancet article linking the MMR vaccine to autism. Its appearance in 1998 fanned the flames of the anti-vaccine movement, with crushing media suspicion falling on the MMR — and a resulting deadly surge in measles cases in the UK and worldwide.

Many large, high-quality studies have since found that Wakefield’s MMR-autism correlation — as well as his cockamamie theory about how the attenuated virus from the vaccine causes gut- and brain-related symptoms — is untrue. Worse, though, is the fact that Wakefield wasn’t just wrong — he was a fraud. He fabricated the medical records of every single one of the children in his study to make it appear as if their autism symptoms had come just after the MMR, whereas many had shown symptoms before, or a long time after, receiving the vaccine.

The publication of the Wakefield paper will forever be a stain on The Lancet, and on the peer-review process of science more generally. Even without the fraud, a study with such earth-shattering implications that only included twelve patients should never have been published somewhere so prominent. Compounding the damage was the sheer amount of time it took for the paper to be officially retracted – an astonishing twelve years. All the while, anti-vaxxers could point to a peer-reviewed study — in The Lancet, no less! — to support their view.

Wakefield was pushing at a door that, while perhaps not fully open, was certainly ajar. The anti-vaccination movement has been with us for a long time — indeed, as long as vaccines. Some renowned historical scientists have been a part of it: for example, Alfred Russel Wallace, who came up with the idea of natural selection independently of Charles Darwin, was an implacable opponent of the smallpox vaccine during the late 19th Century.

Whereas Wallace was certainly a bit “nuts” — he spent a great deal of time trying to convince his peers that spiritualist mediums really could talk to the dead and take photographs of ghosts — his approach to analysing the effects of vaccines (he argued they were actively dangerous) was statistically quite sophisticated for the time. And given that statistics were in such an early phase of their development, the pro-vaccine side hardly had much more convincing data to oppose him.

Wallace also expressed his opposition in terms of anti-paternalism (he wrote that compulsory vaccine laws were “a gross interference with personal liberty and the sanctity of the home”) and even socialism, claiming that vaccines were seen as a quick fix that failed to “get rid of the foul conditions” that caused disease to spread among the poor of Victorian Britain. These arguments were, of course, completely wrong-headed, but they weren’t the ravings of a madman, and they hint at the complexity of the anti-vaccine position: defenders of vaccines need to work on multiple fronts to combat objections that are anything but easily-debunked.

Psychologists are fond of invoking a whole series of cognitive biases to explain why people are irrational about vaccines: the availability heuristic (where people focus too much on a few scary stories at the expense of a more rational appraisal of the situation), omission bias (where having committed an act, like getting your child vaccinated, feels worse if something goes wrong than having not done anything), and so on.

But more recent evidence seems to suggest a simpler reason is at play: if people think there’s a high chance they’ll regret vaccination, they’re less likely to do it. Evidence that we can change people’s beliefs about vaccines for the better is scarce; but changing them for the worse by providing more credible-sounding reasons for regret — like Wakefield’s MMR-autism connection — is much easier.

Alas, the publication of Wakefield’s study is far from the only significant fumble by vaccine scientists and regulators over the years. Relatively soon after his phony paper was published, the US and the EU capitulated to anti-vaccine campaigners on the issue of thiomersal (sometimes spelled thimerosal), a mercury-containing chemical that had long been used as a preservative in vaccines, and had been — you guessed it — linked to autism by the anti-vaxxers.

The idea of injecting mercury into your child’s arm can be made to sound very frightening, but the type of mercury in thiomersal (ethylmercury) isn’t the same as the type we normally discuss with reference to mercury poisoning (methylmercury, which stays in the bloodstream for far longer and can have seriously damaging effects even at small doses). There was never any evidence to support campaigners’ assertions that vaccines containing thiomersal were linked to autism, but something certainly appeared to be going on once the health experts suddenly decided that thiomersal had to go, banning it from almost all vaccines given to children from around the turn of the century.

Those authorities began speaking out of both sides of their mouths, at once saying thiomersal was completely safe and also recommending it should be removed from vaccines “as expeditiously as possible”. What were parents supposed to think? Again, anti-vaccine campaigners used the confusion to boost their message, with a flare-up of the mercury-autism controversy — as well as a plethora of personal injury claims in courts — occurring after the preservative had needlessly been removed from the vaccines.

Not only did the experts put other countries that still used thiomersal in their vaccines — particularly those in the developing world — in an invidious position, they also torpedoed their own future authority. Any use of “completely safe” or “no evidence for adverse effects…” would now be met with references to their seeming lack of straightforwardness on thiomersal.

This history of vaccination gives numerous further examples. The rushed, politicised rollout of the flu vaccine in the US in 1976 — and the potential increase it caused in the rare neurological condition Guillain-Barré Syndrome — has been blamed for spawning anti-vaccine suspicion; as have the catastrophic lab errors that caused live polio viruses to be injected into 200,000 children in 1955, permanently paralysing hundreds and killing ten.

Although safety procedures have since improved dramatically, disasters do still occur, such as the 2016 case of the faulty dengue fever vaccine in the Philippines which ended up making the illness worse. Other failures are not the fault of doctors or scientists, but still produce terrible PR for vaccines: who could forget, for example, the fake vaccination programme used by the CIA to spy on Osama bin Laden’s secret compound and get his family’s DNA?

So do you have to be “nuts” to hesitate about vaccines? Certainly, you have to be somewhat detached from reality to believe, as some do, that Bill Gates is only helping fund the development of a Covid-19 vaccine so he can inject us all with microchips. And to be an anti-vaxxer, you have to be grossly ignorant of the evidence for the near-miraculous effects of vaccination on human wellbeing. But in seeking to persuade those who aren’t hardcore members of the movement, scientists, doctors, and politicians need to learn the lessons from the list of historical precedents where things haven’t gone to plan.

Those lessons are obvious, but underappreciated. We mustn’t underplay any side-effects of the Covid-19 vaccine. We mustn’t provide confident-sounding yet contradictory advice — as we already have during this pandemic in the case of facemasks, first advising that they were useless and maybe even dangerous (which may or may not have been a “noble lie” to preserve mask stocks for healthcare workers), then mandating their use in shops and on public transport. We mustn’t give any credibility to conspiracy theories. And we must above all be honest and transparent about how the vaccine works, who is prioritised to get it and when, and what our targets are for its eventual rollout across the population.

When the Covid-19 vaccine comes — and let’s not hold our breaths, but the early signs are promising — it’ll join the ranks of the most important medical discoveries of all time. Let’s use the failures of the past to inoculate ourselves against errors in the future — and ensure that the vaccine becomes the pandemic-stopper we need it to be.

Stuart Ritchie is the author of, Science Fictions: Exposing Fraud, Bias, Negligence and Hype in Science

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Stuart Ritchie is a psychologist and a Lecturer in the Social, Genetic and Developmental Psychiatry Centre at King’s College London

StuartJRitchie