On 9 April New York City’s mayor Bill de Blasio declared a public health emergency and launched a compulsory vaccination programme in Brooklyn, where at least 285 people have contracted measles since an outbreak began in the autumn. Most of those who have fallen ill are children who had not been vaccinated against a disease that once killed hundreds of Americans a year but that, following a decades-long vaccination programme, was declared eradicated in the US in 2000. The current outbreak is concentrated among the city’s Orthodox Jewish community, but anxiety over immunisation is not confined to this group. In the US, the percentage of children aged under two who are completely unvaccinated has quadrupled since 2001.
The World Health Organization has listed “vaccine hesitancy” among the ten greatest threats to global health in 2019. Writing in the science magazine Nature, Heidi Larson, a professor at the London School of Hygiene and Tropical Medicine, predicted that the next pandemic would not spread for lack of preventative technologies but rather because “emotional contagion, digitally enabled, could erode trust in vaccines so much as to render them moot”.
Larson is also the director of the Vaccine Confidence Project, which surveys public attitudes towards vaccinations and monitors news and social media for misinformation about them. She told me that modern internet culture has played a significant role in stoking fear of vaccinations: in a social media environment that is emotionally volatile, that encourages snap judgement and is mistrustful of elites and authority, misinformation spreads more easily.
Combating misinformation is vital because confidence in vaccinations can decline rapidly in the wake of scare stories. In Denmark, after testimonies by girls who alleged they were harmed by the HPV vaccine, which protects against cervical cancer, were broadcast on TV and online, immunisation rates dropped from 90 per cent for those born from 1998 to 2000 to under 20 per cent for those born five years later.
One of the most notorious cases of bad science gaining traction is the enduring influence of a discredited 1998 study linking the measles mumps and rubella (MMR) vaccination to autism. After serious flaws were uncovered in the research, the study was withdrawn from medical journal the Lancet in 2010 and the study’s author, Andrew Wakefield, struck from the medical register. Subsequent large-scale studies have found no link between the MMR jab and autism – and yet, suspicion persists.
According to Larson, the long afterlife of Wakefield’s findings is the result of a “perfect storm” of factors: the number of parents who believe their child was harmed by the MMR, growing anxiety over rising rates of autism in the West and uncertainty over what is causing it, as well as the expansion of online news and social networking sites.
The Vaccine Confidence Project’s research has also uncovered a generational divide: people aged 18-35 tend to be more sceptical about vaccinations than the over 60s. “Among young adults, there’s a sense of wanting to have self-determination, even a sense of guilt when they haven’t challenged a doctor or an authority figure,” Larson said. It’s perfectly reasonable to ask a doctor questions – but vaccination scepticism may be heightened by the medical community’s failure to respond adequately to patient concerns and fears.
A number of recent studies have sought to uncover the psychology of vaccine scepticism. A 2018 University of Queensland survey of more than 5,000 people in 24 countries found that anti-vaccination beliefs were highest among those who believe in other conspiracies, such as that Princess Diana was murdered or 9/11 was a US government set-up. This suggests that motivated reasoning – the tendency to reject information that doesn’t support one’s world-view – plays a role, and that outlining the facts may not be enough to change minds.
Another Australian study, published earlier this year, suggests that anti-vaxxers often possess a common set of ethical values – one that transcends traditional left-right divides. It found that vaccine sceptics tend to score low on respect for authority and place high value on liberty and “purity”, the belief that certain aspects of life should be inviolable.
Such insights are helpful, but Larson also cautioned against drawing any stark distinctions between “anti-vaxxers” and the rest – arguing that it is both dangerously divisive and inaccurate, because people’s attitudes towards immunisation exist along a spectrum. Online and in the media, vaccinations have become a politically-loaded marker of tribal identity: the New York Times recently ran an editorial on how to “inoculate against anti-vaxxers” and Russian trolls are known to stoke divisions between pro- and anti-vaxxers. Combating unfounded fears of vaccinations will require open, cool-headed, evidence-based debate – something we’re becoming ever worse at.