Not everyone believes in vaccination Max Whittaker/New York Times/Redux/eyevine

Vaccines save lives, so why do some parents prefer not to get their children vaccinated against deadly diseases? It seems the ideas of purity and liberty have a big influence.

Avnika Amin at Emory University, Georgia, and her team surveyed more than 1000 adults in the US who had at least one child aged 12 or younger. They assessed the parents’ attitudes towards vaccinations, as well as how much emphasis they put on each of six moral values: authority, fairness, harm, loyalty, purity and liberty. These values are all known to affect judgement and decision-making. “We thought it might be interesting to see if maybe these intuitive values were associated with health decisions,” says Amin.

The team found that 73 per cent of parents got low scores when it was assessed whether they have concerns about vaccinations, but 11 per cent showed some hesitancy around vaccinations, and 16 per cent were highly hesitant.


Compared with those who weren’t very worried, the medium hesitancy parents were twice as likely to place a high emphasis on purity as a moral value. And high hesitancy parents were twice as likely to emphasise purity and liberty, but half as likely to stress authority, compared with low hesitancy parents.

When the team looked at the claims made on anti-vaccination websites, they found that these often appeal to the same moral values.

Appeal to liberty

A better understanding of how moral values affect vaccination attitudes could help public health officials show parents that childhood vaccinations are actually in line with certain values, says Amin.

For example, for those who see liberty as important, a doctor could stress that vaccination is a way to exercise a parent’s freedom in taking control of their child’s health. “We’re not out to change what people value,” says Amin, “but let’s work with those values to show that we’re on the same side.”

“I think the ideas here are really quite novel,” says Richard Carpiano at the University of California, Riverside. He says we now need to test different types of messaging geared towards these values to see if they can actually change vaccination attitudes.

Journal reference: Nature Human Behaviour, DOI: 10.1038/s41562-017-0256-5