New York, Nov 18 (IANS): You may find it hard to believe but just two organisations in the US are misusing Facebook to post maximum number of anti-vaccine messages to reach targeted audiences, questioning the role of social media in providing a platform to unscientific anti-vaccine messages.

In the first study of public health-related Facebook advertising, published in the journal Vaccine, researchers at the University of Maryland, the George Washington University and Johns Hopkins University found that a small group of anti-vaccine buyers has successfully leveraged Facebook to reach targeted audiences.

The social media platform's efforts to improve transparency have actually led to the removal of ads promoting vaccination and communicating scientific findings, they reported.

The two organisations are the World Mercury Project run by Robert Kennedy Jr, and the Stop Mandatory Vaccinations campaign run by Larry Cook.

The research calls attention to the threat of social media misinformation as it may contribute to increasing "vaccine hesitancy," which the World Health Organisation ranks among the top threats to global health this year.

This increasing reluctance or refusal to vaccinate threatens to reverse the progress made in halting vaccine-preventable diseases, such as measles, which has seen a 30 per cent increase in cases globally.

"The average person might think that this anti-vaccine movement is a grassroots effort led by parents, but what we see on Facebook is that there are a handful of well-connected, powerful people who are responsible for the majority of advertisements. These buyers are more organised than people think," said Amelia Jamison, a faculty research assistant in the Maryland Centre for Health Equity, and the study's first author.

The research team, co-led by Dr Sandra C Quinn, Dr David Broniatowski and Dr Mark Dredze, examined more than 500 vaccine-related ads served to Facebook users and archived in Facebook's Ad Library.

This archive, which became available in late 2018, catalogued ad content related to "issues of national importance."

The findings revealed that the majority of advertisements (54 per cent) which opposed vaccination, were posted by only two groups funded by private individuals, the World Mercury Project and Stop Mandatory Vaccination, and emphasized the purported harms of vaccination.

Because Facebook categorizes ads about vaccines as "political," it has led the platform to reject some pro-vaccine messages.

"By accepting the framing of vaccine opponents -- that vaccination is a political topic, rather than one on which there is widespread public agreement and scientific consensus -- Facebook perpetuates the false idea that there is even a debate to be had," said David Broniatowski, associate professor of engineering management and systems engineering at George Washington University.

This leads to increased vaccine hesitancy, and ultimately, more epidemics.

"Worse, these policies actually penalise pro-vaccine content since Facebook requires disclosure of funding sources for apolitical' ads, but vaccine proponents rarely think of themselves as political. Additionally, vaccine opponents are more organised and more able to make sure that their ads meet these requirements," Broniatowski mentioned.

Facebook is a pervasive presence in the lives of many people, meaning its decisions about how to handle vaccine messaging have far-reaching and serious consequences, said Quinn, a principal investigator on the study.

"In today's social media world, Facebook looms large as a source of information for many, yet their policies have made it more difficult for users to discern what is legitimate, credible vaccine information.

"This puts public health officials, with limited staff resources for social media campaigns, at a true disadvantage, just when we need to communicate the urgency of vaccines as a means to protect our children and our families," Quinn added.

The research team will continue to study how anti-vaccine arguments are spreading on Facebook and how the company is responding to demands from public health organisations to clean up its act.