User-Driven Comments on a Facebook Advertisement Recruiting Canadian Parents in a Study on Immunization: Content Analysis

In light of the fact that more people are searching for immunisation information online and potentially being exposed to misinformation and antivaccination sentiment, this study aimed to explore the sentiments and themes behind an unsolicited debate on immunisation on Facebook in order to better inform public health interventions addressing vaccine noncompliance or hesitancy. Most research to date has focused on analysing the content of discussions on sites or platforms that individuals would find via active research on immunisation. However, there is a gap in research in analysing vaccine information that individuals may see without actively searching for information and could influence decisions on vaccination. This study seeks to fill that gap.

The paper begins by examining the role of the internet in vaccine hesitancy. In Canada, 67% of Canadian internet users are using social media on a daily basis, and Facebook is reported as the most popular social media platform. Health information communicated in such interactive platforms is of questionable accuracy, as it is often exchanged without the participation of health professionals or health organisations. According to researchers, dissemination of negative information online and lack of knowledge about vaccines may be contributing to suboptimal vaccination coverage among Canadian children and increases in vaccine-preventable disease rates. Results from the 2013 Childhood National Immunization Coverage Survey show that 70% of Canadian parents surveyed reported being concerned about potential side effects of vaccines, and 37% believed that vaccines can cause disease.

From December 12 2013 to January 11 2014, the researchers posted 6 different Facebook advertisements linked to a Web-based survey on childhood immunisations to the Facebook News Feeds of Canadian parents as part of a larger research study (see Related Summaries, below, for details). The advertisements did not provide any information on immunisation, did not try to solicit discussion, and were not posted, shared, liked, or promoted by the researchers. The Comments section of the advertisements was accessible, and this created an unsolicited and spontaneous discourse where users posted comments on immunisation to the 2 most viewed advertisements.

For the present study, on January 11 2014, the researchers analysed and quantified 117 user-driven open-ended comments on immunisation posted in the Comments section. Then, 2 raters coded all comments using content analysis. Of 117 comments, 85 were posted by unique commentators, with most being female (65/85, 77%). The majority of the comments were comments only (103/117, 88.0%), and and 11.9% (14/117) posted links to websites. Of the 14 website links, 2 were from trustworthy sources, with 1 linked to a trustworthy source with accurate information (a government website with official statistics) and 1 linked to an online news story with accurate information posted from a government source.

The largest proportion of the immunisation comments were positive (51/117, 43.6%), followed by negative (41/117, 35.0%), ambiguous (20/117, 17.1%), and hesitant (5/117, 4.3%). (These subcategories were based on the themes of determinants of vaccine hesitancy suggested by the World Health Organization (WHO)'s Strategic Advisory Group of Experts Working Group (SAGE WG) on Immunization. The SAGE WG matrix organises vaccine sentiment into 3 domains: contextual influences, such as socioeconomic barriers, mistrust in the pharmaceutical industry, or religious values; individual and social group influences, such as personal knowledge or perceptions of risk; and vaccination and vaccination-specific issues, such as the vaccination schedule or characteristics of the vaccine.) Comments with the most interaction (20 or more likes) had mostly positive main messages (8/9, 89%) and 1 negative.

In the 66 negative, hesitant, or ambiguous comments, 130 claims were made on factors affecting vaccination decisions. Individual and social group influence was the predominant theme in the claims within the posted comments (85/130, 65.4%). Inaccurate knowledge (27/130, 20.8%) and misperceptions of risk (23/130, 17.7%) were most prevalent in the 130 nonpositive comments. Other claims included distrust of pharmaceutical companies or government agencies (18/130, 13.8%), distrust of the healthcare system or providers (15/130, 11.5%), past negative experiences with vaccination or beliefs (10/130, 7.7%), and attitudes about health and prevention (10/130, 7.7%). Parents' right to choose and not be judged was an important theme among the negative comments; the researchers stress that the issue of freedom and individual rights versus the notion of social good "needs to be given careful thought in our communications on issues such as mandatory vaccination and exemption rights."

In the 51 positive comments (and 2 hesitant comments with positive claims), we identified 74 claims on factors affecting vaccination decisions. Within these comments, the majority (29/74, 39%) of the positive claims communicated the risks of not vaccinating, followed by judgments on the knowledge level of nonvaccinators (13/74, 18%). Ten positive comments (10/74, 14%) specifically refuted the link between autism and vaccination. Although the majority of the positive comments did not provide any links or obvious information from health authorities, there was encouragement to seek out trusted sources and people.

Reflecting on the findings, the researchers suggest that "Identified themes, such as the perceived risk of adverse events versus the risk of disease, and misinformation on autism and other disorders, immunity, and vaccine ingredients, could be addressed with more communication messages tailored to the issues in the online discussions. Although some antivaccination activists may never be swayed by evidence, it is important for health authorities to provide information to those with genuine concerns or questions, and engage in online debates rapidly in a nonjudgmental and transparent manner."

Along those lines, "we need to better understand who should be engaging online to rebut misinformation and spread accurate and scientifically valid information on immunization. Mistrust in health care professionals and the government has been reported as an important determinant in vaccine hesitancy...; thus, alternative spokespeople (eg, influential mommy bloggers or celebrities) may need to be considered in the delivery of expert-based information. However, a recent survey of Canadian adults reported that the majority trust physicians and public health officials for timely and credible vaccine information....Further research is needed to determine the extent of public health involvement, and what interventions or messaging and by whom would have the most impact online." What does seem to be clear is that "Online silence from public health authorities could give the impression of agreement with antivaccination information or sentiment...; thus, public health departments need to be proactive in their social media strategies by promoting the safety of vaccines and addressing misinformation with targeted and tested interventions and messaging."

In conclusion: "The random nature of online debates will present a challenge for health authorities in terms of monitoring and engagement. Monitoring will need to include data mining with algorithms for keywords on immunization to quickly identify and engage in all public online communications on immunization. Health authorities need to identify methods to better leverage online platforms and networks in order to build trust, increase knowledge and access to information, and contest misinformation and misperceptions. It would also be important to consider appropriate jurisdictional responsibilities among health authorities for online surveillance and communications in immunization discussions."