Vaccine hesitancy has become a legitimate public health threat in recent years. Confounding governments and health care advocates, the phenomenon sees parents delay or refuse to have their children vaccinated despite both the availability of immunization services and overwhelming evidence supporting vaccination.
Why are parents turning away from a tried and true practice for protecting their children? A new Canadian study enlists the help of Facebook to get to the bottom of the problem.
One of the most crucial advances in modern medicine, vaccines for infectious diseases are said to have saved more lives in Canada than any other public health measure, and the World Health Organization lists 25 diseases that are vaccine-preventable, including measles, mumps, cholera, tuberculosis and hepatitis A and B.
Yet a decline in vaccination rates across the developed world has hampered immunization efforts and raised the spectre of outbreaks of diseases once thought to be eliminated.
A recent study in the United States found that just a five-per cent decrease in measles-mumps-and-rubella (MMR) vaccination in children aged two to 11 years would triple the number of cases of measles, a disease that had been declared eliminated in the US in 2000.
Canada has seen outbreaks of measles and mumps in recent years, which have come hand-in-hand with immunization rates that linger below the herd immunity threshold, which typically requires up to 95 per cent of an at-risk population to be vaccinated.
And vaccine hesitancy —defined as those in the mid-range between total acceptance of vaccination and complete refusal— is a significant threat. While getting your child vaccinated is still the norm in Canada, a 2016 survey found that a full 70 per cent of parents said that they were concerned about potential side effects from vaccines and 37 per cent believed (erroneously) that a vaccine can cause the same disease it is meant to prevent.
“There is a critical need to better understand the factors underlying vaccine hesitancy in Canada in order to implement interventions to help parents in their decision to vaccinate and increase vaccine coverage,” say the authors of a new study published in the journal JMIR Public Health Surveillance.
The go-to approach to surveying people’s opinions on immunization has been random digit dialing (RDD), yet with fewer households owning landlines (only 56 per cent as of 2013), access to the full range of opinions is now limited through RDD.
Facebook campaign targets anti-vaxxers
To that end, researchers from Ryerson University, the University of Toronto, Toronto Public Health and Concordia University of Edmonton turned to Facebook, the most common social media platform in Canada, using targeted ads on the site to recruit 1696 participants who filled out their web-based survey on vaccination.
The approach was able to specifically target their sought-after demographic: parents of children aged zero to 15 years, with the results significantly skewed towards female respondents (91.43 per cent). They found that 26.62 per cent of respondents reported perceiving childhood immunizations as unsafe to moderately safe and 21.1 per cent of respondents saying that the decision of whether or not to vaccinate their child was either “difficult or very difficult.”
Importantly, respondents said that the availability of controversial or contradicting information about vaccinations was a major contributor to vaccine hesitancy, along with respondents saying that there was not enough unbiased or trustworthy information to be found on the topic.
The results provide valuable insights for future public health directives, say the study’s authors, and show that social media platforms can be key in reaching targeted populations.
“Targeted recruitment via Facebook was successful in reaching a population more likely to be engaging in health discussions on the Internet and making decisions on childhood immunizations,” say the study’s authors. “Thus, this recruitment strategy was superior to the RDD methodology in reaching ‘at-risk’ vaccine-hesitant parents.”
Earlier this year, the World Health Organization issued a report that said a record number of measles cases were reported in Europe in 2018, due in part to growing pockets of the population where parents are refusing to immunize their children.