Dr Cornelia Betsch, a psychologist at the University of Erfurt in Germany, says that the Internet is perceived by users to have a very low importance in health decisions, with people tending to say they use information provided by their doctors and traditional media.
Research suggests that around half of those surveyed in ten European countries use the Internet to search for health information, and this figure has been rising.
However, online information is likely to have a greater role than is often believed. “The fact that individuals report that they do not consider the Internet to be an important source does not necessarily mean that the information obtained in their frequent Internet searches does not influence their decisions. Internet information may still have an influence, if rather subtle,” Dr Betsch writes.
She said psychological research has shown that influence on perceptions and behaviour is not always conscious, making it difficult to accurately assess its impact using simple surveys.
Online information: high in quantity, low in quality?
The accuracy of online information about vaccines varies widely, according to Dr Betsch. A study of Internet searches during the 2009 H1N1 flu pandemic for the term “hand cleaning” led to WHO information 75-80% of the time.
“In contrast, only 51% of the information sources found regarding the relationship between MMR vaccine and autism gave the correct answer,” she writes, in an article published in the journal Eurosurveillance.
Similarly, in a US study analysing the first 10 hits on Google.com for the search terms “vaccination”, “vaccine”, and “immunization”, 21 of the total 30 results were immunisation sites of which five were anti-vaccine.
The number of anti-vaccination sites varies depending on the search term. More specific search terms turned up fewer anti-vaccine sites. This suggests that a typical web surfer, coming to an issue for the first time and using broad search terms, will be presented with the least accurate sample of web pages.
“This means that the people with less knowledge on the topic, who are more likely to conduct searches, will do so using less complex search terms which lead to more anti-vaccination websites,” according to Dr Betsch.
Research suggests that most anti-vaccine sites use emotive appeals, such as pictures and stories of children who were supposedly harmed by vaccinations. Parents appear to have a preference for personal information when searching for health related topics, often using internet forums, the paper states.
User-generated content – on Facebook, Twitter and other social networking sites – also rely heavily on personal information. During the flu pandemic, 22.5% of flu-related tweets contained person experiences of illness or vaccination.
The impact of social media sites probably leads to an under-estimation of the availability of anti-vaccination narratives on the internet, Dr Betsch says.
The kind of stories people read about vaccines is proven to change their opinion. Psychological research in Germany which examined vaccine risk perceptions before and after reading websites showed that those who read neutral content perceived less risk than those who read vaccine-critical Internet sites. Indeed, the latter served to increase readers’ fears.
The impact is real and lasting. Children of parents who perceive high risks after the internet search were likely to have received fewer vaccines after five months than children whose parents had viewed neutral vaccine information.
The paper, which itself has been widely spread through social media channels by journalists and health authorities, warns against using fear as a communication tool, saying this can prove counterproductive.
Dr Betsch suggests that one strategy for getting the vaccine story across is to inform the public about why the typical objections of anti-vaccination activists are false. One effective example is the ‘20 objections and responses’ published by the Robert Koch Institute in Germany.