Anti-vaccine websites are misinforming parents, study says

Childhood vaccines are key to preventing diseases and epidemics, but growing numbers of parents choose to delay or refuse vaccination, for a variety of reasons. The Internet is often cited as a source of vaccine information – and also controversy.

In previous comparisons of pro-vaccine and anti-vaccine websites, pro-vaccination sites were found to focus on evidence-based scientific research about vaccines and government-endorsed vaccination-related practices.

In contrast, anti-vaccine websites focus on creating communities of people affected by vaccines and vaccine-related practices, creating a personal framework that is used to challenge the information presented in the scientific literature and government documents.

Mainstream health communities are concerned about the lack of success in persuading parents who do not wish to vaccinate, despite the use of educational and misinformation-correcting messages.

Unvaccinated people at risk of disease

In 2014, the Centers for Disease Control and Prevention (CDC) recorded the highest number of measles cases since measles was declared eliminated in 2000.

The majority of those who caught it were unvaccinated. The CDC state that measles can spread when it reaches a community where groups of people have not received the vaccine. If the percentage of people vaccinated against measles, for example, is below 92%, this dramatically increases the chance of an epidemic.

Lead author of the current study, Meghan Moran, associate professor in the Bloomberg School’s Department of Health, Behavior and Society, and colleagues wanted to understand the strategies through which anti-vaccine advocates create such strongly held anti-vaccine attitudes – and to use this insight to develop more effective vaccine promotion strategies.

They examined four search engines, Google, Bing, Yahoo and Ask Jeeves, using terms like “immunization dangers” and “vaccine danger,” and others identified using Google Trends.

After eliminating duplicates, they had a mix of nearly 500 personal websites and blogs, Facebook pages and health websites.

The content was analyzed for persuasive strategies used, as well as for the specific beliefs about vaccines being presented, including vaccine misinformation and its sources.

Two thirds of anti-vaccine sites ‘are misleading’

The team also coded websites for lifestyle indicators, in order to identify additional values, attitudes, behaviors and preferences associated with the anti-vaccine movement. Through analyzing behaviors and values co-promoted by the websites, they hoped to develop better-targeted materials that could help promote vaccination.

Misinformation was common in the anti-vaccine websites: 65.6% claim that vaccines are dangerous, 62.2% that they cause autism and 41.1% that they cause “brain injury.” To support these claims, 64.7% used scientific evidence and 30% used anecdotes.

Regarding values, 41% mentioned choice, 20.5% freedom and 17.4% individuality.

Use of alternative medicine was promoted by 18.8% of sites and homeopathy by 10.2%. Healthy diet was promoted in 18.5% of cases, and 5.2% supported an organic diet. In 7.1% of websites, cleansing one’s body of toxins was promoted, 5.5% supported breastfeeding and 6.8% co-promoted religiosity.

Moran says:

“The biggest global takeaway is that we need to communicate to the vaccine-hesitant parent in a way that resonates with them and is sensitive to their concerns. In our review, we saw communication for things we consider healthy, such as breastfeeding, eating organic, the types of behavior public health officials want to encourage. I think we can leverage these good things and reframe our communication in a way that makes sense to those parents resisting vaccines for their children.”

Understanding the strategies used to further an anti-vaccine message is useful for the development of strategies to counteract the negative messages and promote childhood vaccinations. Gaining an in-depth understanding of the broader culture supporting anti-vaccine decisions can help to inform tailored pro-vaccine education and advocacy messages.

Fast facts about vaccination

  • 83% of children aged 19-35 months old are fully vaccinated against diphtheria, tetanus,pertussis (DTaP)
  • 93% are fully vaccinated against polio
  • 92% are vaccinated against measles, mumps and rubella (MMR).