Anti-vaxxers have similar beliefs around being persecuted as conspiracy theorists and their networks are immune to outside influences, new Australian research suggests.
A big data study just published by Australian National University (ANU) and Federation University analysed almost 300,000 text comments from around 14,700 individual posts on six anti-vaccination Facebook pages from Australia and North America.
"When we analysed what individuals said in these comments, we identified similar topics to conspiracy theorists," said Dr Tim Graham, a postdoctoral research fellow at ANU's College of Engineering and Computer Science and the ANU School of Sociology.
"They believe the government and the media underplay, deny and perpetuate perceived harms caused by vaccinations."
The research also found the anti-vaccination movement might be less close-knit than previously assumed.
"Most users of the pages we studied appeared to be transient; they came on, commented on a few posts and then you never see them again."
The networks were found to be "small world" - meaning that information spreads extremely rapidly throughout the network and the networks were resilient to attack or outside influence.
"Interestingly, there was also a significant gender skew," Graham said.
"Three-quarters of those involved in the anti-vaccination Facebook pages were women. This is reflective of vaccination still being perceived as 'a mother's question'."
The research, funded through a seed grant provided by Federation University, comes amid concerns from some health professionals that anti-vaccination sentiment is on the rise in New Zealand, despite an overwhelming scientific consensus that vaccination is safe and has massively cut rates of mortality from infectious diseases.
New Zealand's Environmental Protection Agency recently also listed anti-vaccination as among areas where misinformed views were being reinforced and nurtured in what it called the "unmoderated milieu" of the internet.
While the Ministry of Health has goals to increase immunisation rates to 95 per cent for 8-month-olds, the latest coverage rate report found that, over the three months to December, the number fell short of that mark at 92 per cent.
It was also down on coverage rates at the same time in 2016 (93.3 per cent) and in 2015 (93.7 per cent).