Expressions of doubt are essential for promoting trust in vaccines, research has revealed.
The University of Limerick (UL) study, analysing data from more than 140 countries, has revealed that partially convinced people can help in spreading trust toward vaccination as part of a “human chain of influence”.
“Mapping the global opinion space to explain anti‑vaccine attraction”, which has recently been published in the journal Scientific Reports, said the presence of people expressing some doubts over vaccination is crucial for promoting trust.
“Effective vaccines are our first line of defence against infectious diseases and future pandemics, but are useless if people cannot be persuaded to use them,” said Dr Dino Carpentras, lead author of the study.
“How is it that people who have questions about vaccines so easily end up on the side of vaccine sceptics? This is the question we asked in the research.
“People talk to each other every day, shaping each other’s opinions. In our study we wanted to analyse how this happens, and if it could help us explain why neutral people are more persuaded by the vaccine sceptics.”
The team started with the idea that the more similar two people’s attitudes are, the more they will be able to influence each other.
They then used computational models to test how this affects the propagation of trust in society.
“The results of the models are clear,” said Dr Carpentras.
“Having enough people expressing minor reservations about vaccination can limit the influence of vaccine sceptics.”
Dr Adrian Luders, a co-author on the study and post-doctoral researcher at UL, said: “If you have some doubts about vaccination, then who will be most open to discussing them with you?
“A person with complete trust will struggle to influence a neutral person, as they are too different.
“However, a partial truster could act as an intermediary between the two, producing a human chain of influence.”
Further analysis confirmed that countries that had a “break in the chain” between the positive and the neutral position toward vaccination performed worse.
The weaker the chain of influence between people with full trust and neutral people, the lower level of vaccine coverage in the following year, and the larger the increase in the number of vaccine sceptics.